Avoid using f64 to lower memcpy from constant string. It's cheaper to use i32 store of immediates.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100751 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 678f636..9362d37 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -1067,18 +1067,22 @@
}
/// getOptimalMemOpType - Returns the target specific optimal type for load
-/// and store operations as a result of memset, memcpy, and memmove lowering.
-/// If DstAlign is zero that means it's safe to destination alignment can
-/// satisfy any constraint. Similarly if SrcAlign is zero it means there
-/// isn't a need to check it against alignment requirement, probably because
-/// the source does not need to be loaded. If 'NonScalarIntSafe' is true, that
-/// means it's safe to return a non-scalar-integer type, e.g. constant string
-/// source or loaded from memory. It returns EVT::Other if SelectionDAG should
-/// be responsible for determining it.
+/// and store operations as a result of memset, memcpy, and memmove
+/// lowering. If DstAlign is zero that means it's safe to destination
+/// alignment can satisfy any constraint. Similarly if SrcAlign is zero it
+/// means there isn't a need to check it against alignment requirement,
+/// probably because the source does not need to be loaded. If
+/// 'NonScalarIntSafe' is true, that means it's safe to return a
+/// non-scalar-integer type, e.g. empty string source, constant, or loaded
+/// from memory. 'MemcpyStrSrc' indicates whether the memcpy source is
+/// constant so it does not need to be loaded.
+/// It returns EVT::Other if SelectionDAG should be responsible for
+/// determining the type.
EVT
X86TargetLowering::getOptimalMemOpType(uint64_t Size,
unsigned DstAlign, unsigned SrcAlign,
bool NonScalarIntSafe,
+ bool MemcpyStrSrc,
SelectionDAG &DAG) const {
// FIXME: This turns off use of xmm stores for memset/memcpy on targets like
// linux. This is because the stack realignment code can't handle certain
@@ -1095,11 +1099,14 @@
return MVT::v4i32;
if (Subtarget->hasSSE1())
return MVT::v4f32;
- } else if (Size >= 8 &&
+ } else if (!MemcpyStrSrc && Size >= 8 &&
!Subtarget->is64Bit() &&
Subtarget->getStackAlignment() >= 8 &&
- Subtarget->hasSSE2())
+ Subtarget->hasSSE2()) {
+ // Do not use f64 to lower memcpy if source is string constant. It's
+ // better to use i32 to avoid the loads.
return MVT::f64;
+ }
}
if (Subtarget->is64Bit() && Size >= 8)
return MVT::i64;
@@ -6721,7 +6728,7 @@
Count, InFlag);
InFlag = Chain.getValue(1);
Chain = DAG.getCopyToReg(Chain, dl, Subtarget->is64Bit() ? X86::RDI :
- X86::EDI,
+ X86::EDI,
Dst, InFlag);
InFlag = Chain.getValue(1);
Chain = DAG.getCopyToReg(Chain, dl, Subtarget->is64Bit() ? X86::RSI :