[LLVMdev] [PATCH] Detect Haswell subarchitecture (i.e. using -march=native)

[Adam Strzelecki]

> I promise I'll do the review of your code after that.

Tim, I don’t want to push too much. But since there’s 3.4 release on the horizon, maybe you could find a moment review this patch. Especially Haswell is all there since few months.

Cheers,
-- 
Adam

---
 lib/Support/Host.cpp            | 8 ++++++++
 lib/Target/X86/X86Subtarget.cpp | 3 ++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/lib/Support/Host.cpp b/lib/Support/Host.cpp
index 380df6b..2235456 100644
--- a/lib/Support/Host.cpp
+++ b/lib/Support/Host.cpp
@@ -138,6 +138,8 @@ std::string sys::getHostCPUName() {
   // switch, then we have full AVX support.
   const unsigned AVXBits = (1 << 27) | (1 << 28);
   bool HasAVX = ((ECX & AVXBits) == AVXBits) && OSHasAVXSupport();
+  bool HasAVX2 = HasAVX && !GetX86CpuIDAndInfo(0x7, &EAX, &EBX, &ECX, &EDX) &&
+                 (EBX & 0x20);
   GetX86CpuIDAndInfo(0x80000001, &EAX, &EBX, &ECX, &EDX);
   bool Em64T = (EDX >> 29) & 0x1;
 
@@ -258,6 +260,12 @@ std::string sys::getHostCPUName() {
         // versions instead of the i7 versions).
         return HasAVX ? "core-avx-i" : "corei7";
 
+      // Haswell:
+      case 60:
+        // Not all Haswell processors support AVX too (such as the Pentium
+        // versions instead of the i7 versions).
+        return HasAVX2 ? "core-avx2" : "corei7";
+
       case 28: // Most 45 nm Intel Atom processors
       case 38: // 45 nm Atom Lincroft
       case 39: // 32 nm Atom Medfield
diff --git a/lib/Target/X86/X86Subtarget.cpp b/lib/Target/X86/X86Subtarget.cpp
index fa04c38..d221316 100644
--- a/lib/Target/X86/X86Subtarget.cpp
+++ b/lib/Target/X86/X86Subtarget.cpp
@@ -285,7 +285,8 @@ void X86Subtarget::AutoDetectSubtargetFeatures() {
          (Family == 6 && Model == 0x2F) || // Westmere: Westmere-EX
          (Family == 6 && Model == 0x2A) || // SandyBridge
          (Family == 6 && Model == 0x2D) || // SandyBridge: SandyBridge-E*
-         (Family == 6 && Model == 0x3A))) {// IvyBridge
+         (Family == 6 && Model == 0x3A) || // IvyBridge
+         (Family == 6 && Model == 0x3C))) {// Haswell
       IsUAMemFast = true;
       ToggleFeature(X86::FeatureFastUAMem);
     }
-- 
1.8.3.4 (Apple Git-47)