[mips] Remap move as or.
Summary:
This patch remaps the assembly idiom 'move' to 'or' instead of 'daddu' or
'addu'. The use of addu/daddu instead of or as move was highlighted as a
performance issue during the analysis of a recent 64bit design. Originally
move was encoded as 'or' by binutils but was changed for the r10k cpu family
due to their pipeline which had 2 arithmetic units and a single logical unit,
and so could issue multiple (d)addu based moves at the same time but only 1
logical move.
This patch preserves the disassembly behaviour so that disassembling a old style
(d)addu move still appears as move, but assembling move always gives an or
Patch by Simon Dardis.
Reviewers: vkalintiris
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D11796
llvm-svn: 244579
diff --git a/llvm/lib/Target/Mips/MipsAsmPrinter.cpp b/llvm/lib/Target/Mips/MipsAsmPrinter.cpp
index 027c4e2..88b54b5 100644
--- a/llvm/lib/Target/Mips/MipsAsmPrinter.cpp
+++ b/llvm/lib/Target/Mips/MipsAsmPrinter.cpp
@@ -1008,7 +1008,7 @@
//
// Mov $18, $31
- EmitInstrRegRegReg(*STI, Mips::ADDu, Mips::S2, Mips::RA, Mips::ZERO);
+ EmitInstrRegRegReg(*STI, Mips::OR, Mips::S2, Mips::RA, Mips::ZERO);
EmitSwapFPIntParams(*STI, Signature->ParamSig, LE, true);