aaron/ispc
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Call CPUID to more reliably detect level of SSE/AVX that the host supports.

Browse Source 
Fixes, I hope, issue #205.
This commit is contained in:
Matt Pharr
2012-03-28 09:20:06 -07:00
parent 013a3e7567
commit 3270e2bf5a
1 changed files with 46 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

55
ispc.cpp
View File

@@ -70,6 +70,49 @@ Module *m;
///////////////////////////////////////////////////////////////////////////
// Target
#ifndef ISPC_IS_WINDOWS
static void __cpuid(int info[4], int infoType) {
__asm__ __volatile__ ("cpuid"
: "=a" (info[0]), "=b" (info[1]), "=c" (info[2]), "=d" (info[3])
: "0" (infoType));
}
/* Save %ebx in case it's the PIC register */
static void __cpuidex(int info[4], int level, int count) {
__asm__ __volatile__ ("xchg{l}\t{%%}ebx, %1\n\t"
"cpuid\n\t"
"xchg{l}\t{%%}ebx, %1\n\t"
: "=a" (info[0]), "=r" (info[1]), "=c" (info[2]), "=d" (info[3])
: "0" (level), "2" (count));
}
#endif // ISPC_IS_WINDOWS
static const char *
lGetSystemISA() {
int info[4];
__cpuid(info, 1);
if ((info[2] & (1 << 28)) != 0) {
// AVX1 for sure. Do we have AVX2?
// Call cpuid with eax=7, ecx=0
__cpuidex(info, 7, 0);
if ((info[1] & (1 << 5)) != 0)
return "avx2";
else
return "avx";
}
else if ((info[2] & (1 << 19)) != 0)
return "sse4";
else if ((info[3] & (1 << 26)) != 0)
return "sse2";
else {
fprintf(stderr, "Unable to detect supported SSE/AVX ISA. Exiting.\n");
exit(1);
}
}
bool
Target::GetTarget(const char *arch, const char *cpu, const char *isa,
bool pic, Target *t) {
@@ -85,15 +128,9 @@ Target::GetTarget(const char *arch, const char *cpu, const char *isa,
t->cpu = cpu;
if (isa == NULL) {
if (!strcasecmp(cpu, "atom"))
isa = "sse2";
#if defined(LLVM_3_0) || defined(LLVM_3_0svn) || defined(LLVM_3_1svn)
else if (!strcasecmp(cpu, "sandybridge") ||
!strcasecmp(cpu, "corei7-avx"))
isa = "avx";
#endif // LLVM_3_0
else
isa = "sse4";
isa = lGetSystemISA();
fprintf(stderr, "Notice: no --target specified on command-line. Using "
"system ISA \"%s\".\n", isa);
}
if (arch == NULL)
arch = "x86-64";