Use MOVSSmr instead of EXTRACTPSmr in the case of extracting
vector element 0 for a store, as it's smaller and faster.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58483 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 7e1b7a0..cdf1670 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -4194,11 +4194,15 @@
} else if (VT == MVT::f32) {
// EXTRACTPS outputs to a GPR32 register which will require a movd to copy
// the result back to FR32 register. It's only worth matching if the
- // result has a single use which is a store or a bitcast to i32.
+ // result has a single use which is a store or a bitcast to i32. And in
+ // the case of a store, it's not worth it if the index is a constant 0,
+ // because a MOVSSmr can be used instead, which is smaller and faster.
if (!Op.hasOneUse())
return SDValue();
SDNode *User = *Op.getNode()->use_begin();
- if (User->getOpcode() != ISD::STORE &&
+ if ((User->getOpcode() != ISD::STORE ||
+ (isa<ConstantSDNode>(Op.getOperand(1)) &&
+ cast<ConstantSDNode>(Op.getOperand(1))->isNullValue())) &&
(User->getOpcode() != ISD::BIT_CONVERT ||
User->getValueType(0) != MVT::i32))
return SDValue();