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Fix bugs in detection of Ivy Bridge systems.

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We were incorrectly characterizing them as basic AVX1 without further
extensions, due to a bug in the logic to check CPU features.
This commit is contained in:
Matt Pharr
2012-07-12 14:10:59 -07:00
parent d180031ef0
commit 371d4be8ef
2 changed files with 48 additions and 48 deletions
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26
ispc.cpp
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@@ -94,20 +94,22 @@ 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 {
// ivybridge?
if ((info[2] & (1 << 29)) != 0 && // F16C
(info[2] & (1 << 30)) != 0) // RDRAND
return "avx1.1";
if ((info[2] & (1 << 28)) != 0) { // AVX
// AVX1 for sure....
// Ivy Bridge?
if ((info[2] & (1 << 29)) != 0 && // F16C
(info[2] & (1 << 30)) != 0) { // RDRAND
// So far, so good. AVX2?
// Call cpuid with eax=7, ecx=0
int info2[4];
__cpuidex(info2, 7, 0);
if ((info2[1] & (1 << 5)) != 0)
return "avx2";
else
return "avx";
return "avx1.1";
}
// Regular AVX
return "avx";
}
else if ((info[2] & (1 << 19)) != 0)
return "sse4";