[X86][MMX] Improve handling of 64-bit MMX constants
64-bit MMX constant generation usually ends up lowering into SSE instructions before being spilled/reloaded as a MMX type.
This patch bitcasts the constant to a double value to allow correct loading directly to the MMX register.
I've added MMX constant asm comment support to improve testing, it's better to always print the double values as hex constants as MMX is mainly an integer unit (and even with 3DNow! its just floats).
Differential Revision: https://reviews.llvm.org/D43616
llvm-svn: 326497
diff --git a/llvm/lib/Target/X86/X86MCInstLower.cpp b/llvm/lib/Target/X86/X86MCInstLower.cpp
index 730ba745..f5f87c1 100644
--- a/llvm/lib/Target/X86/X86MCInstLower.cpp
+++ b/llvm/lib/Target/X86/X86MCInstLower.cpp
@@ -1822,6 +1822,24 @@
break;
}
+ case X86::MMX_MOVQ64rm: {
+ if (!OutStreamer->isVerboseAsm())
+ break;
+ if (MI->getNumOperands() <= 4)
+ break;
+ if (auto *C = getConstantFromPool(*MI, MI->getOperand(4))) {
+ std::string Comment;
+ raw_string_ostream CS(Comment);
+ const MachineOperand &DstOp = MI->getOperand(0);
+ CS << X86ATTInstPrinter::getRegisterName(DstOp.getReg()) << " = ";
+ if (auto *CF = dyn_cast<ConstantFP>(C)) {
+ CS << "0x" << CF->getValueAPF().bitcastToAPInt().toString(16, false);
+ OutStreamer->AddComment(CS.str(), !EnablePrintSchedInfo);
+ }
+ }
+ break;
+ }
+
#define MOV_CASE(Prefix, Suffix) \
case X86::Prefix##MOVAPD##Suffix##rm: \
case X86::Prefix##MOVAPS##Suffix##rm: \