Messages du vectoriseur et du paralléliseur
Vous pouvez utiliser les options /Qpar-report du compilateur Microsoft C++ et /Qvec-report définir la parallélisation automatique et la vectorisation automatique pour générer des codes de raison et des messages d’information sur son activité. Cet article explique les code motifs et les messages.
Messages d'information
Selon le niveau de rapport que vous spécifiez, l'un des messages d'information suivants apparait pour chaque boucle.
Pour plus d'informations sur les codes motifs, consultez la partie suivante de cet article.
| Message d’information | Description |
|---|---|
| 5001 | Boucle vectorisée. |
| 5002 | Boucle non vectorisée en raison de la raison « description ». |
| 5011 | Boucle parallélisée. |
| 5012 | Boucle non parallélisée en raison de la raison « description ». |
| 5,021 | Impossible d'associer la boucle au pragma. |
Les sections suivantes répertorient les codes de raison possibles pour le paralléliseur et le vectoriseur.
Codes de raison 5xx
Les codes de raison 5xx s’appliquent à la fois au paralléliseur et au vectoriseur.
| Code motif | Explication |
|---|---|
| 500 | Message générique qui couvre plusieurs cas : Par exemple, la boucle inclut plusieurs sorties, ou l’en-tête de boucle ne se termine pas par incrémenter la variable d’induction. |
| 501 | La variable d’induction n’est pas locale ; ou limite supérieure n’est pas invariante de boucle. |
| 502 | La variable d'induction est incrémentée de manière différente que le simple +1. |
| 503 | La boucle inclut la gestion des exceptions ou des instructions switch. |
| 504 | Le corps de la boucle peut lever une exception qui requiert la destruction de l'objet C++. |
| 505 | La boucle externe a une variable d’induction pré incrémentée. Sortie de l’analyse. |
void code_500(int *A)
{
// Code 500 is emitted if the loop has non-vectorizable flow.
// This can include "if", "break", "continue", the conditional
// operator "?", or function calls.
// It also encompasses correct definition and use of the induction
// variable "i", in that the increment "++i" or "i++" must be the last
// statement in the loop.
int i = 0;
while (i<1000)
{
if (i == 4)
{
break;
}
++i;
A[i] = A[i] + 1;
}
// To resolve code 500, use a 'for' loop with single increment of
// induction variable.
for (int i=0; i<1000; ++i)
{
A[i] = A[i] + 1;
}
}
int bound();
void code_501_example1(int *A)
{
// Code 501 is emitted if the compiler cannot discern the
// induction variable of this loop. In this case, when it checks
// the upper bound of 'i', the compiler cannot prove that the
// function call "bound()" returns the same value each time.
// Also, the compiler cannot prove that the call to "bound()"
// does not modify the values of array A.
for (int i=0; i<bound(); ++i)
{
A[i] = A[i] + 1;
}
// To resolve code 501, ensure that the induction variable is
// a local variable, and ensure that the upper bound is a
// provably loop invariant value.
for (int i=0, imax = bound(); i<imax; ++i)
{
A[i] = A[i] + 1;
}
}
int i;
void code_501_example2(int *A)
{
// Code 501 is emitted if the compiler cannot discern the
// induction variable of this loop. In this case, 'i' is
// a global.
for (i=0; i<1000; ++i)
{
A[i] = A[i] + 1;
}
// To resolve code 501, ensure that the induction variable is
// a local variable, and ensure that the upper bound is a
// provably loop invariant value.
for (int i=0; i<1000; ++i)
{
A[i] = A[i] + 1;
}
}
void code_502(int *A)
{
// Code 502 is emitted if the compiler cannot discern
// the induction variable of the loop. In this case,
// there are three increments to "i", one of which
// is conditional.
for (int i=0; i<1000; ++i)
{
A[i] = A[i] + 1;
++i;
if (i < 100)
{
++i;
}
}
// To resolve code 502, ensure that there is just one
// increment of the induction variable, placed in the usual
// spot in the "for" loop.
for (int i=0; i<1000; ++i)
{
A[i] = A[i] + 1;
}
}
void code_503(int *A, int x)
{
// Code 503 is emitted if there are inadmissible
// operations in the loop - for example, exception handling and
// switch statements.
for (int i = 0; i<1000; ++i)
{
switch (x)
{
case 1: A[i] = A[i] + 1;
case 2: A[i] = A[i] + 2;
case 3: A[i] = A[i] + 3;
break;
}
}
// To resolve code 503, try to remove as many switch statements
// and exception handling constructs as possible.
}
// compile with /EHsc
int code_504_helper();
class C504
{
public:
C504();
~C504();
};
void code_504(int *A)
{
// Code 504 is emitted if a C++ object was created and
// that object requires EH unwind tracking information under
// /EHs or /EHsc.
for(int i = 0; i < 1000; ++i)
{
C504 c;
A[i] = code_504_helper();
}
}
void code_505(int *A)
{
// Code 505 is emitted on outer loops with pre-incremented
// induction variables. The vectorizer/parallelizer analysis
// package doesn't support these loops, and they are
// intentionally not converted to post-increment loops to
// prevent a performance degradation.
// To parallelize an outer loop that causes code 505, change
// it to a post-incremented loop.
for (int i=100; i--; )
for (int j=0; j<100; j++) { // this loop is still vectorized
A[j] = A[j] + 1;
}
}
Codes de raison 10xx
Les codes de raison 10xx s’appliquent au paralléliseur.
| Code motif | Explication |
|---|---|
| 1 000 | Le compilateur a détecté une dépendance de données dans le corps de la boucle. |
| 1001 | Le compilateur a détecté un enregistrement d'une variable scalaire dans le corps de la boucle, et ce scalaire est utilisée après la boucle. |
| 1002 | Le compilateur a tenté de paralléliser une boucle qui a une boucle interne déjà parallélisée. |
| 1003 | Le corps de la boucle contient un appel intrinsèque qui peut lire ou écrire dans la mémoire. |
| 1004 | Il existe une réduction scalaire dans le corps de la boucle. La réduction scalaire peut se produire si la boucle a été vectorisée. |
| 1005 | Le no_parallel pragma a été spécifié. |
| 1006 | Cette fonction contient OpenMP. Résolvez-le en supprimant n’importe quel OpenMP dans cette fonction. |
| 1007 | La variable d’induction de boucle ou les limites de la boucle ne sont pas des nombres 32 bits signés (int ou long). Résolvez-le en modifiant le type de la variable d’induction. |
| 1008 | Le compilateur a détecté que cette boucle ne fonctionne pas suffisamment pour justifier la parallélisation automatique. |
| 1009 | Le compilateur a détecté une tentative de paralléliser une boucle «do-while ». Le paralléliseur automatique cible uniquement les boucles «for ». |
| 1010 | Le compilateur a détecté que la boucle utilise « non égal » (!=) pour sa condition. |
int A[1000];
void func();
void code_1000()
{
// Code 1000 is emitted if the compiler detects a
// data dependence in the loop body.
// You can resolve this by using the ivdep pragma.
// CAUTION -- the compiler will trust your
// assertion that there are no data dependencies
// in the loop body. If there are, you are generating
// code that may have race conditions.
#pragma loop(hint_parallel(0))
//#pragma loop(ivdep) // ivdep will force this through.
for (int i=0; i<1000; ++i)
{
A[i] = A[i-1] + 1; // data dependence here
func(); // data dependence here
}
}
int code_1001()
{
// Code 1001 is emitted if the compiler detects
// a store to a scalar variable in the loop
// body, and that scalar has a use beyond the loop.
// Resolve this by rewriting your code so
// that the scalar is not needed.
int s = 0;
#pragma loop(hint_parallel(0))
for (int i=0; i<1000; ++i)
{
s = A[i];
}
return s;
}
void code_1002()
{
// Code 1002 is emitted when the compiler tries to
// parallelize a loop that has an inner loop that
// has already been parallelized.
#pragma loop(hint_parallel(0))
for (int i=0; i<1000; ++i) // emit code 1002 for this loop
{
#pragma loop(hint_parallel(0))
for (int j=0; j<1000; ++j) // this loop gets parallelized
{
A[j] = A[j] + 1;
}
}
}
extern "C" void __stosb(unsigned char*, unsigned char, size_t);
void code_1003(unsigned char *dst)
{
// Code 1003 is emitted when the loop body contains an intrinsic
// call that may read or write to memory.
// This can be resolved by using the ivdep pragma.
// CAUTION -- the compiler will trust your
// assertion that there are no data dependencies
// in the loop body. If there are, you are generating
// code that may have race conditions.
#pragma loop(hint_parallel(0))
//#pragma loop(ivdep) // ivdep will force this through.
for (int i=0; i<1000; ++i)
{
__stosb(dst, 'c', 10);
A[i] = A[i] + 1;
}
}
int code_1004()
{
// Code 1004 is emitted when there is a scalar reduction
// in the loop body, which can occur if the loop has been
// vectorized.
// You can resolve this by rewriting your code so that it
// does not have a scalar reduction.
int s = 0;
#pragma loop(hint_parallel(0))
for (int i=0; i<1000; ++i)
{
s += A[i];
}
return s;
}
void code_1005()
{
// Code 1005 is emitted when the
// no_parallel pragma is specified.
#pragma loop(no_parallel)
for (int i=0; i<1000; ++i)
{
A[i] = A[i] + 1;
}
}
#include <omp.h>
// Compile with /openmp
void code_1006()
{
// Code 1006 is emitted when this function contains
// openmp. Resolve this by removing any openmp in this
// function.
for (int i=0; i<1000; ++i)
{
A[i] = A[i] + 1;
}
#pragma omp parallel num_threads(4)
{
int i = omp_get_thread_num();
A[i] = A[i] + 1;
}
}
void code_1007()
{
// Code 1007 is emitted when the loop induction variable
// or the loop bounds are not signed 32-bit numbers (int
// or long). Resolve this by changing the type of the
// induction variable.
#pragma loop(hint_parallel(0))
for (unsigned int i=0; i<1000; ++i)
{
A[i] = A[i] + 1;
}
}
void code_1008()
{
// Code 1008 is emitted when the compiler detects that
// this loop does not perform enough work to warrant
// auto-parallelization.
// You can resolve this by specifying the hint_parallel
// pragma. CAUTION -- if the loop does not perform
// enough work, parallelizing might cause a potentially
// large performance penalty.
// #pragma loop(hint_parallel(0)) // hint_parallel will force this through
for (int i=0; i<1000; ++i)
{
A[i] = A[i] + 1;
}
}
void code_1009()
{
// Code 1009 is emitted when the compiler tries to parallelize a
// "do-while" loop. The auto-parallelizer only targets "for" loops.
int i = 0;
#pragma loop(hint_parallel(0))
do
{
A[i] = A[i] + 1;
}
while (++i < 1000);
}
void code_1010()
{
// Code 1010 is emitted when the compiler tries to parallelize a
// loop with a condition code of "!=".
// You can resolve this by replacing it with an ordering comparator
// like "<".
#pragma loop(hint_parallel(0))
for (int i = 0; i != 1000; ++i)
{
A[i]++;
}
}
Codes de raison 11xx
Les codes de raison 11xx s’appliquent au vectoriseur.
| Code motif | Explication |
|---|---|
| 1100 | La boucle contient un flux de contrôle( par exemple, «if » ou «?: ». |
| 1101 | La boucle contient une conversion de type de données (éventuellement implicite) qui ne peut pas être vectorisée. |
| 1102 | La boucle comporte des opérations non-arithmétiques, ou autres, non vectorisables. |
| 1103 | Le corps de la boucle inclut les opérations de décalage dont la taille peut varier dans la boucle. |
| 1104 | Le corps de la boucle inclut des variables scalaires. |
| 1105 | La boucle inclut une opération de réduction non reconnue. |
| 1106 | Boucle externe non vectorisée. |
void code_1100(int *A, int x)
{
// Code 1100 is emitted when the compiler detects control flow
// in the loop - for example, "if", the ternary operator "?", and
// the like. Resolve this by flattening or removing control
// flow in the loop body.
// Not all control flow causes 1100; some is indeed
// vectorized.
for (int i=0; i<1000; ++i)
{
// straight line code is more amenable to vectorization
if (x)
{
A[i] = A[i] + 1;
}
}
}
extern "C" int __readcr0();
void code_1102(int *A)
{
// Code 1102 is emitted when the compiler is unable to vectorize
// an operation in the loop body. For example, intrinsics and other
// non-arithmetic, non-logical, and non-memory operations are not
// vectorizable.
// Resolve this by removing as many non-vectorizable operations
// as possible from the loop body.
for (int i=0; i<1000; ++i)
{
A[i] = __readcr0();
}
}
void code_1103(int *A, int *B)
{
// Code 1103 is emitted when the compiler is unable to vectorize
// a "shift" operation. In this example, there are two shifts
// that cannot be vectorized.
for (int i=0; i<1000; ++i)
{
A[i] = A[i] >> B[i]; // not vectorizable
int x = B[i];
A[i] = A[i] >> x; // not vectorizable
}
// To resolve this, ensure that your shift amounts are loop
// invariant. If the shift amounts cannot be loop invariant,
// it may not be possible to vectorize this loop.
int x = B[0];
for (int i=0; i<1000; ++i)
{
A[i] = A[i] >> x; // vectorizable
}
}
int code_1104(int *A, int *B)
{
// When it vectorizes a loop, the compiler must 'expand' scalar
// variables to a vector size such that they can fit in
// vector registers. Code 1104 is emitted when the compiler
// cannot 'expand' such scalars.
// In this example, we try to 'expand' x to be used in the
// vectorized loop. However, there is a use of 'x'
// beyond the loop body, which prohibits this expansion.
// To resolve this, try to limit scalars to be used only in
// the loop body and not beyond, and try to keep their types
// consistent with the loop types.
int x;
for (int i=0; i<1000; ++i)
{
x = B[i];
A[i] = A[i] + x;
}
return x;
}
int code_1105(int *A)
{
// The compiler performs an optimization that's known as "reduction"
// when it operates on each element of an array and computes
// a resulting scalar value - for example, in this piece of code, which
// computes the sum of each element in the array:
int s = 0;
for (int i=0; i<1000; ++i)
{
s += A[i]; // vectorizable
}
// The reduction pattern must resemble the loop in the example. The
// compiler emits code 1105 if it cannot deduce the reduction
// pattern, as shown in this example:
for (int i=0; i<1000; ++i)
{
s += A[i] + s; // code 1105
}
// Similarly, reductions of "float" or "double" types require
// that the /fp:fast switch is thrown. Strictly speaking,
// the reduction optimization that the compiler performs uses
// "floating point reassociation". Reassociation is only
// allowed when /fp:fast is thrown.
return s;
}
void code_1106(int *A)
{
// Code 1106 is emitted when the compiler tries to vectorize
// an outer loop.
for (int i=0; i<1000; ++i) // this loop is not vectorized
{
for (int j=0; j<1000; ++j) // this loop is vectorized
{
A[j] = A[j] + 1;
}
}
}
Codes de raison 12xx
Les codes de raison 12xx s’appliquent au vectoriseur.
| Code motif | Explication |
|---|---|
| 1 200 | La boucle contient des dépendances de données portées par une boucle qui empêchent la vectorisation. Différentes itérations de la boucle interfèrent entre elles de telle sorte que la vectorisation de la boucle produit des réponses incorrectes et que le vectoriseur automatique ne peut pas se prouver qu’il n’existe pas de telles dépendances de données. |
| 1201 | Modifications de base du tableau pendant la boucle. |
| 1202 | Le champ d’un struct n’est pas large de 32 ou 64 bits. |
| 1203 | Le corps de la boucle inclut des accès non contigus dans un tableau. |
| 1204 | Limite de limite de structure de données interne du compilateur : trop de périphéries de dépendance de données. |
void fn();
void code_1200(int *A)
{
// Code 1200 is emitted when data dependence is prohibiting
// vectorization. This can only be resolved by rewriting the
// loop, and considering the marking of loop function calls as
// __forceinline.
for (int i=0; i<1000; ++i)
{
A[i] = A[i-1] + 1; // vectorization-prohibiting
fn(); // vectorization-prohibiting
}
}
void code_1201(int *A)
{
// Code 1201 is emitted when an array base changes
// in the loop body. Resolve this by rewriting your
// code so that varying the array base is not necessary.
for (int i=0; i<1000; ++i)
{
A[i] = A[i] + 1;
A++;
}
}
struct S_1202
{
short a;
short b;
} s[1000];
short sA[1000], sB[1000], sC[1000];
void code_1202(S_1202 *s)
{
// Code 1202 is emitted when non-vectorizable struct accesses
// are present in the loop body. Only struct accesses
// that are 32 or 64 bits are vectorized.
for (int i=0; i<1000; ++i)
{
s[i].a = s[i].b + 1; // this 16 bit struct access is not vectorizable
sA[i] += sB[i] * sC[i]; // this ensures we don't emit reason code '1300'
}
}
void code_1203(int *A)
{
// Code 1203 is emitted when non-vectorizable memory references
// are present in the loop body. Vectorization of some non-contiguous
// memory access is supported - for example, the gather/scatter pattern.
for (int i=0; i<1000; ++i)
{
A[i] += A[0] + 1; // constant memory access not vectorized
A[i] += A[i*2+2] + 2; // non-contiguous memory access not vectorized
}
}
void code_1204(int *A)
{
// Code 1204 is emitted when internal compiler data structures
// hit a limit on the number of data dependence edges recorded.
// Resolve this by moving the innermost loop to another function.
for (int i=0; i<1000; i++)
for (int j=0; j<1000; j++)
for (int k=0; k<1000; k++)
for (int l=0; l<1000; l++)
{
for (int m=0; m<1000; m++)
A[m] = A[m+i] + A[m+j] + A[m+k] + A[m+l];
}
}
Codes de raison 13xx
Les codes de raison 13xx s’appliquent au vectoriseur.
| Code motif | Explication |
|---|---|
| 1 300 | Le corps de la boucle contient peu ou pas de calcul. |
| 1301 | La progression de la boucle n’est pas +1. |
| 1302 | La boucle est un «do-while ». |
| 1303 | Il existe trop peu d'itérations de boucle pour que la vectorisation apporte une valeur quelconque. |
| 1304 | La boucle inclut des affectations qui sont de différentes tailles. |
| 1305 | Pas assez d'informations de type. |
void code_1300(int *A, int *B)
{
// Code 1300 is emitted when the compiler detects that there is
// no computation in the loop body.
for (int i=0; i<1000; ++i)
{
A[i] = B[i]; // Do not vectorize, instead emit memcpy
}
}
void code_1301(int *A)
{
// Code 1301 is emitted when the stride of a loop is not positive 1.
// Only loops that have a stride of positive 1 are vectorized;
// rewriting your loop may be required.
for (int i=0; i<1000; i += 2)
{
A[i] = A[i] + 1;
}
}
void code_1302(int *A)
{
// Code 1302 is emitted for "do-while" loops. Only "while"
// and "for" loops are vectorized.
int i = 0;
do
{
A[i] = A[i] + 1;
} while (++i < 1000);
}
int code_1303(int *A, int *B)
{
// Code 1303 is emitted when the compiler detects that
// the number of iterations of the loop is too small to
// make vectorization profitable.
// If the loop computation fits perfectly in
// vector registers - for example, the upper bound is 4, or 8 in
// this case - then the loop _may_ be vectorized.
// This loop is not vectorized because there are 5 iterations
for (int i=0; i<5; ++i)
{
A[i] = A[i] + 1;
}
// This loop is vectorized
for (int i=0; i<4; ++i)
{
A[i] = A[i] + 1;
}
// This loop is not vectorized because runtime pointer checks
// are required to check that A and B don't overlap. It is not
// worth it to vectorize this loop.
for (int i=0; i<4; ++i)
{
A[i] = B[i] + 1;
}
// This loop is not vectorized because of the scalar reduction.
int s = 0;
for (int i=0; i<4; ++i)
{
s += A[i];
}
return s;
}
void code_1304(int *A, short *B)
{
// Code 1304 is emitted when the compiler detects
// different sized statements in the loop body.
// In this case, there is an 32-bit statement and a
// 16-bit statement.
// In cases like this consider splitting the loop into loops to
// maximize vector register utilization.
for (int i=0; i<1000; ++i)
{
A[i] = A[i] + 1;
B[i] = B[i] + 1;
}
}
typedef struct S_1305
{
int a;
int b;
} S_1305;
void code_1305( S_1305 *s, S_1305 x)
{
// Code 1305 is emitted when the compiler can't discern
// proper vectorizable type information for this loop.
// This includes non-scalar loop types such as struct
// assignments, as in this example.
// Resolve this by ensuring that your loops have statements
// that operate on integers or floating point types.
for (int i=0; i<1000; ++i)
{
s[i] = x;
}
}
Codes de raison 14xx
Les codes de raison 14xx se produisent quand une option incompatible avec la vectorisation est spécifiée.
| Code motif | Explication |
|---|---|
| 1400 | #pragma loop(no_vector) est spécifié. |
| 1401 | /kernel le commutateur est spécifié lors du ciblage de x86 ou ARM. |
| 1402 | /arch:SSE2 ou un commutateur supérieur n’est pas spécifié lors du ciblage de x86. |
| 1403 | /arch:ATOM le commutateur est spécifié et la boucle inclut des opérations sur des doubles. |
| 1404 | /O1 ou /Os commutateur est spécifié. |
| 1405 | La vectorisation est désactivée pour faciliter l'optimisation du passage d'un initialiseur statique à un initialiseur dynamique. |
void code_1400(int *A)
{
// Code 1400 is emitted when the no_vector pragma
// is specified.
#pragma loop(no_vector)
for (int i=0; i<1000; ++i)
{
A[i] = A[i] + 1;
}
}
// Compile with /kernel
void code_1401(int *A)
{
// Code 1401 is emitted when /kernel is specified.
for (int i=0; i<1000; ++i)
{
A[i] = A[i] + 1;
}
}
// Compile with /arch:IA32
void code_1402(int *A)
{
// Code 1401 is emitted when /arch:IA32 is specified.
for (int i=0; i<1000; ++i)
{
A[i] = A[i] + 1;
}
}
// Compile with /favor:ATOM
void code_1403(double *A)
{
// Code 1401 is emitted when /favor:ATOM is specified, and
// the loop contains operations on "double" arrays.
for (int i=0; i<1000; ++i)
{
A[i] = A[i] + 1;
}
}
// Compile with /O1 or /Os
void code_1404(int *A)
{
// Code 1401 is emitted when compiling for size.
for (int i=0; i<1000; ++i)
{
A[i] = A[i] + 1;
}
}
Codes de raison 15xx
Les codes de raison 15xx s’appliquent à l’alias. L'attribution d'alias se produit lorsqu'un emplacement mémoire est accessible par deux noms différents.
| Code motif | Explication |
|---|---|
| 1 500 | Alias possible sur des tableaux multidimensionnels. |
| 1501 | Alias possible sur des tableaux de struct. |
| 1502 | L'alias possible et l'index de tableau sont différents de n + K. |
| 1503 | L'alias possible et l'index de tableau ont plusieurs décalages. |
| 1504 | L'attribution d'alias nécessiterait trop de vérifications à l'exécution. |
| 1505 | L'attribution d'alias est possible, mais les vérifications à l'exécution sont trop complexes. |
void code_1500(int A[100][100], int B[100][100])
{
// Code 1500 is emitted when runtime pointer
// disambiguation checks are required, and
// there are multidimensional array references.
for (int i=0; i<100; ++i)
{
for (int j=0; j<100; ++j)
{
A[i][j] = B[i][j] + 1;
}
}
}
typedef struct S_1501
{
int a;
int b;
} S_1501;
int iA[1000], iB[1000], iC[1000];
void code_1501(S_1501 *s1, S_1501 *s2)
{
// Code 1501 is emitted when runtime pointer
// disambiguation checks are required, and
// there are array-of-struct accesses in the
// loop body.
for (int i=0; i<100; ++i)
{
s1[i].a = s2[i].b + 1;
iA[i] += iB[i] * iC[i]; // this is to ensure we don't emit reason code '1300'
}
}
void code_1502(int *A, int *B)
{
// Code 1502 is emitted when runtime pointer
// disambiguation checks are required, and
// an array reference has an offset that varies
// in the loop.
int x = 0;
for (int i=0; i<100; ++i)
{
A[i] = B[i + x] + 1;
++x; // 'x' varies in the loop
}
}
void code_1503(int *A, int *B, int x, int y)
{
// Code 1503 is emitted when runtime pointer
// disambiguation checks are required, and
// an array reference has multiple offsets.
for (int i=0; i<100; ++i)
{
A[i] = B[i+x] + B[i+y] + 1; // multiple offsets when addressing 'B': {x, y}
A[i] = B[i+x] + B[i] + 1; // multiple offsets when addressing 'B': {x, 0}
A[i] = B[i+x] + B[i+x] + 1; // this is vectorized
}
}
void code_1504(int *A1, int *A2, int *A3, int *A4,
int *A5, int *A6, int *A7, int *A8,
int *A9, int *A10, int *A11, int *A12,
int *A13, int *A14, int *A15, int *A16)
{
// Code 1504 is emitted when too many runtime
// pointer disambiguation checks are required.
for (int i=0; i<100; ++i)
{
++A1[i];
++A2[i];
++A3[i];
++A4[i];
++A5[i];
++A6[i];
++A7[i];
++A8[i];
++A9[i];
++A10[i];
++A11[i];
++A12[i];
++A13[i];
++A14[i];
++A15[i];
++A16[i];
}
}
void code_1505(int *A, int *B)
{
// Code 1505 is emitted when runtime pointer
// disambiguation checks are required, but are
// too complex for the compiler to discern.
for (int i=0; i<100; ++i)
{
for (int j=0; j<100; ++j)
{
for (int k=0; k<100; ++k)
{
A[i+j-k] = B[i-j+k] * 2;
}
}
}
}
Voir aussi
Erreurs et avertissements du compilateur C/C++ et des outils de génération
Parallélisation automatique et vectorisation automatique
Vectoriseur automatique dans Visual Studio 2012 – Vue d’ensemble
#pragma loop()
/Q Options (opérations de bas niveau)
/Qpar-report (Niveau de création de rapports de paralléliseur automatique)
/Qvec-report (Niveau de création de rapports de vectoriseur automatique)