call libc memcpy/memset if array size is bigger then threshold.
Coping 100MB array (after a warmup) shows that glibc 2.6.1 implementation on
x86-64 (core 2) is 30% faster (from 0.270917s to 0.188079s)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41479 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 6673c5f..75fbd44 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -3753,10 +3753,10 @@
if (Align == 0) Align = 1;
ConstantSDNode *I = dyn_cast<ConstantSDNode>(Op.getOperand(3));
- // If not DWORD aligned, call memset if size is less than the threshold.
+ // If not DWORD aligned or size is more than the threshold, call memset.
// It knows how to align to the right boundary first.
if ((Align & 3) != 0 ||
- (I && I->getValue() < Subtarget->getMinRepStrSizeThreshold())) {
+ (I && I->getValue() > Subtarget->getMinRepStrSizeThreshold())) {
MVT::ValueType IntPtr = getPointerTy();
const Type *IntPtrTy = getTargetData()->getIntPtrType();
TargetLowering::ArgListTy Args;
@@ -3909,10 +3909,10 @@
if (Align == 0) Align = 1;
ConstantSDNode *I = dyn_cast<ConstantSDNode>(Op.getOperand(3));
- // If not DWORD aligned, call memcpy if size is less than the threshold.
+ // If not DWORD aligned or size is more than the threshold, call memcpy.
// It knows how to align to the right boundary first.
if ((Align & 3) != 0 ||
- (I && I->getValue() < Subtarget->getMinRepStrSizeThreshold())) {
+ (I && I->getValue() > Subtarget->getMinRepStrSizeThreshold())) {
MVT::ValueType IntPtr = getPointerTy();
TargetLowering::ArgListTy Args;
TargetLowering::ArgListEntry Entry;
diff --git a/test/CodeGen/X86/2004-02-12-Memcpy.llx b/test/CodeGen/X86/2004-02-12-Memcpy.llx
index 8cd9a50..56b8d3b 100644
--- a/test/CodeGen/X86/2004-02-12-Memcpy.llx
+++ b/test/CodeGen/X86/2004-02-12-Memcpy.llx
@@ -1,24 +1,26 @@
-; RUN: llvm-upgrade < %s | llvm-as | llc -march=x86 | grep movs
-declare void %llvm.memcpy.i32(sbyte* %A, sbyte* %B, uint %amt, uint %align)
+; RUN: llvm-as < %s | llc -march=x86 | grep movs | count 1
+; RUN: llvm-as < %s | llc -march=x86 | grep memcpy | count 2
-%A = global [1000 x int] zeroinitializer
-%B = global [1000 x int] zeroinitializer
+@A = global [32 x i32] zeroinitializer
+@B = global [32 x i32] zeroinitializer
+declare void @llvm.memcpy.i32(i8*, i8*, i32, i32)
-void %main() {
+define void @main() {
; dword copy
- call void %llvm.memcpy.i32(sbyte* cast (int* getelementptr ([1000 x int]* %A, long 0, long 0) to sbyte*),
- sbyte* cast (int* getelementptr ([1000 x int]* %B, long 0, long 0) to sbyte*),
- uint 4000, uint 4)
+ call void @llvm.memcpy.i32(i8* bitcast ([32 x i32]* @A to i8*),
+ i8* bitcast ([32 x i32]* @B to i8*),
+ i32 128, i32 4 )
; word copy
- call void %llvm.memcpy.i32(sbyte* cast (int* getelementptr ([1000 x int]* %A, long 0, long 0) to sbyte*),
- sbyte* cast (int* getelementptr ([1000 x int]* %B, long 0, long 0) to sbyte*),
- uint 4000, uint 2)
+ call void @llvm.memcpy.i32( i8* bitcast ([32 x i32]* @A to i8*),
+ i8* bitcast ([32 x i32]* @B to i8*),
+ i32 128, i32 2 )
; byte copy
- call void %llvm.memcpy.i32(sbyte* cast (int* getelementptr ([1000 x int]* %A, long 0, long 0) to sbyte*),
- sbyte* cast (int* getelementptr ([1000 x int]* %B, long 0, long 0) to sbyte*),
- uint 4000, uint 1)
+ call void @llvm.memcpy.i32( i8* bitcast ([32 x i32]* @A to i8*),
+ i8* bitcast ([32 x i32]* @B to i8*),
+ i32 128, i32 1 )
+
ret void
}