Address a FIXME and update the fast unaligned memory feature for newer

Intel chips.

The model number rules were determined by inspecting Intel's
documentation for their newer chip model numbers. My understanding is
that all of the newer Intel chips have fast unaligned memory access, but
if anyone is concerned about a particular chip, just shout.

No tests updated; it's not clear we have dedicated tests for the chips'
various features, but if anyone would like tests (or can point me at
some existing ones), I'm happy to oblige.

llvm-svn: 169730

2 files changed, 21 insertions, 13 deletions

diff --git a/llvm/lib/Target/X86/X86.td b/llvm/lib/Target/X86/X86.td
index 8ad0bc08ac5..e3c22d9c3b8 100644
--- a/llvm/lib/Target/X86/X86.td
+++ b/llvm/lib/Target/X86/X86.td
@@ -182,17 +182,17 @@ def : Proc<"westmere",        [FeatureSSE42, FeatureCMPXCHG16B,
 // Sandy Bridge
 // SSE is not listed here since llvm treats AVX as a reimplementation of SSE,
 // rather than a superset.
-def : Proc<"corei7-avx",      [FeatureAVX, FeatureCMPXCHG16B, FeaturePOPCNT,
-                               FeatureAES, FeaturePCLMUL]>;
+def : Proc<"corei7-avx",      [FeatureAVX, FeatureCMPXCHG16B, FeatureFastUAMem,
+                               FeaturePOPCNT, FeatureAES, FeaturePCLMUL]>;
 // Ivy Bridge
-def : Proc<"core-avx-i",      [FeatureAVX, FeatureCMPXCHG16B, FeaturePOPCNT,
-                               FeatureAES, FeaturePCLMUL,
+def : Proc<"core-avx-i",      [FeatureAVX, FeatureCMPXCHG16B, FeatureFastUAMem,
+                               FeaturePOPCNT, FeatureAES, FeaturePCLMUL,
                                FeatureRDRAND, FeatureF16C, FeatureFSGSBase]>;
 
 // Haswell
-def : Proc<"core-avx2",       [FeatureAVX2, FeatureCMPXCHG16B, FeaturePOPCNT,
-                               FeatureAES, FeaturePCLMUL, FeatureRDRAND,
-                               FeatureF16C, FeatureFSGSBase,
+def : Proc<"core-avx2",       [FeatureAVX2, FeatureCMPXCHG16B, FeatureFastUAMem,
+                               FeaturePOPCNT, FeatureAES, FeaturePCLMUL,
+                               FeatureRDRAND, FeatureF16C, FeatureFSGSBase,
                                FeatureMOVBE, FeatureLZCNT, FeatureBMI,
                                FeatureBMI2, FeatureFMA,
                                FeatureRTM]>;
diff --git a/llvm/lib/Target/X86/X86Subtarget.cpp b/llvm/lib/Target/X86/X86Subtarget.cpp
index 34f9fad6969..bdce4d0221b 100644
--- a/llvm/lib/Target/X86/X86Subtarget.cpp
+++ b/llvm/lib/Target/X86/X86Subtarget.cpp
@@ -234,12 +234,20 @@ void X86Subtarget::AutoDetectSubtargetFeatures() {
       ToggleFeature(X86::FeatureSlowBTMem);
     }
 
-    // If it's Nehalem, unaligned memory access is fast.
-    // Include Westmere and Sandy Bridge as well.
-    // FIXME: add later processors.
-    if (IsIntel && ((Family == 6 && Model == 26) ||
-        (Family == 6 && Model == 44) ||
-        (Family == 6 && Model == 42))) {
+    // If it's an Intel chip since Nehalem and not an Atom chip, unaligned
+    // memory access is fast. We hard code model numbers here because they
+    // aren't strictly increasing for Intel chips it seems.
+    if (IsIntel &&
+        ((Family == 6 && Model == 0x1E) || // Nehalem: Clarksfield, Lynnfield,
+                                           //          Jasper Froest
+         (Family == 6 && Model == 0x2A) || // Nehalem: Bloomfield, Nehalem-EP
+         (Family == 6 && Model == 0x2E) || // Nehalem: Nehalem-EX
+         (Family == 6 && Model == 0x25) || // Westmere: Arrandale, Clarksdale
+         (Family == 6 && Model == 0x2C) || // Westmere: Gulftown, Westmere-EP
+         (Family == 6 && Model == 0x2F) || // Westmere: Westmere-EX
+         (Family == 6 && Model == 0x2A) || // SandyBridge
+         (Family == 6 && Model == 0x2D) || // SandyBridge: SandyBridge-E*
+         (Family == 6 && Model == 0x3A))) {// IvyBridge
       IsUAMemFast = true;
       ToggleFeature(X86::FeatureFastUAMem);
     }