Avoid using lossy load / stores for memcpy / memset expansion. e.g.

f64 load / store on non-SSE2 x86 targets.

llvm-svn: 169944

2 files changed, 11 insertions, 0 deletions

diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index 88282c7331b..de7159e474a 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -9481,6 +9481,10 @@ EVT ARMTargetLowering::getOptimalMemOpType(uint64_t Size,
   return MVT::Other;
 }
 
+bool ARMTargetLowering::isLegalMemOpType(MVT VT) const {
+  return VT.isInteger() || VT == MVT::f64 || VT == MVT::v2f64;
+}
+
 bool ARMTargetLowering::isZExtFree(SDValue Val, EVT VT2) const {
   if (Val.getOpcode() != ISD::LOAD)
     return false;
diff --git a/llvm/lib/Target/ARM/ARMISelLowering.h b/llvm/lib/Target/ARM/ARMISelLowering.h
index 5a44201ec48..3e78ae3b2d5 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.h
+++ b/llvm/lib/Target/ARM/ARMISelLowering.h
@@ -296,6 +296,13 @@ namespace llvm {
                                     bool MemcpyStrSrc,
                                     MachineFunction &MF) const;
 
+    /// isLegalMemOpType - Returns true if it's legal to use load / store of the
+    /// specified type to expand memcpy / memset inline. This is mostly true
+    /// for legal types except for some special cases. For example, on X86
+    /// targets without SSE2 f64 load / store are done with fldl / fstpl which
+    /// also does type conversion.
+    virtual bool isLegalMemOpType(MVT VT) const;
+
     using TargetLowering::isZExtFree;
     virtual bool isZExtFree(SDValue Val, EVT VT2) const;