[llvm-commits] [llvm] r100089 - in /llvm/trunk/lib/Target/X86: X86.td X86Subtarget.cpp X86Subtarget.h

[Evan Cheng]

Author: evancheng
Date: Thu Apr  1 00:58:17 2010
New Revision: 100089

URL: http://llvm.org/viewvc/llvm-project?rev=100089&view=rev
Log:
Nehalem unaligned memory access is fast.

Modified:
    llvm/trunk/lib/Target/X86/X86.td
    llvm/trunk/lib/Target/X86/X86Subtarget.cpp
    llvm/trunk/lib/Target/X86/X86Subtarget.h

Modified: llvm/trunk/lib/Target/X86/X86.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86.td?rev=100089&r1=100088&r2=100089&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86.td (original)
+++ llvm/trunk/lib/Target/X86/X86.td Thu Apr  1 00:58:17 2010
@@ -59,6 +59,9 @@
                                       [FeatureCMOV]>;
 def FeatureSlowBTMem : SubtargetFeature<"slow-bt-mem", "IsBTMemSlow", "true",
                                        "Bit testing of memory is slow">;
+def FeatureFastUAMem : SubtargetFeature<"fast-unaligned-mem",
+                                        "IsUAMemFast", "true",
+                                        "Fast unaligned memory access">;
 def FeatureSSE4A   : SubtargetFeature<"sse4a", "HasSSE4A", "true",
                                       "Support SSE 4a instructions">;
 
@@ -98,8 +101,10 @@
 def : Proc<"core2",           [FeatureSSSE3,  Feature64Bit, FeatureSlowBTMem]>;
 def : Proc<"penryn",          [FeatureSSE41,  Feature64Bit, FeatureSlowBTMem]>;
 def : Proc<"atom",            [FeatureSSE3,   Feature64Bit, FeatureSlowBTMem]>;
-def : Proc<"corei7",          [FeatureSSE42,  Feature64Bit, FeatureSlowBTMem]>;
-def : Proc<"nehalem",         [FeatureSSE42,  Feature64Bit, FeatureSlowBTMem]>;
+def : Proc<"corei7",          [FeatureSSE42,  Feature64Bit, FeatureSlowBTMem,
+                               FeatureFastUAMem]>;
+def : Proc<"nehalem",         [FeatureSSE42,  Feature64Bit, FeatureSlowBTMem,
+                               FeatureFastUAMem]>;
 // Sandy Bridge does not have FMA
 def : Proc<"sandybridge",     [FeatureSSE42,  FeatureAVX,   Feature64Bit]>;
 

Modified: llvm/trunk/lib/Target/X86/X86Subtarget.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86Subtarget.cpp?rev=100089&r1=100088&r2=100089&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86Subtarget.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86Subtarget.cpp Thu Apr  1 00:58:17 2010
@@ -266,6 +266,9 @@
     unsigned Model  = 0;
     DetectFamilyModel(EAX, Family, Model);
     IsBTMemSlow = IsAMD || (Family == 6 && Model >= 13);
+    // If it's Nehalem, unaligned memory access is fast.
+    if (Family == 15 && Model == 26)
+      IsUAMemFast = true;
 
     GetCpuIDAndInfo(0x80000001, &EAX, &EBX, &ECX, &EDX);
     HasX86_64 = (EDX >> 29) & 0x1;
@@ -286,6 +289,7 @@
   , HasFMA3(false)
   , HasFMA4(false)
   , IsBTMemSlow(false)
+  , IsUAMemFast(false)
   , HasVectorUAMem(false)
   , DarwinVers(0)
   , stackAlignment(8)

Modified: llvm/trunk/lib/Target/X86/X86Subtarget.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86Subtarget.h?rev=100089&r1=100088&r2=100089&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86Subtarget.h (original)
+++ llvm/trunk/lib/Target/X86/X86Subtarget.h Thu Apr  1 00:58:17 2010
@@ -78,6 +78,9 @@
   /// IsBTMemSlow - True if BT (bit test) of memory instructions are slow.
   bool IsBTMemSlow;
 
+  /// IsUAMemFast - True if unaligned memory access is fast.
+  bool IsUAMemFast;
+
   /// HasVectorUAMem - True if SIMD operations can have unaligned memory
   ///                  operands. This may require setting a feature bit in the
   ///                  processor.
@@ -148,6 +151,7 @@
   bool hasFMA3() const { return HasFMA3; }
   bool hasFMA4() const { return HasFMA4; }
   bool isBTMemSlow() const { return IsBTMemSlow; }
+  bool isUnalignedMemAccessFast() const { return IsUAMemFast; }
   bool hasVectorUAMem() const { return HasVectorUAMem; }
 
   bool isTargetDarwin() const { return TargetType == isDarwin; }