Implement a small optimization, which papers over the problem in
X86/2004-04-13-FPCMOV-Crash.llx
A more robust fix is to follow.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12935 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/InstSelectSimple.cpp b/lib/Target/X86/InstSelectSimple.cpp
index 6958979..775833c 100644
--- a/lib/Target/X86/InstSelectSimple.cpp
+++ b/lib/Target/X86/InstSelectSimple.cpp
@@ -1038,7 +1038,18 @@
FalseVal = ConstantExpr::getCast(F, Type::ShortTy);
}
-
+ unsigned TrueReg = getReg(TrueVal, MBB, IP);
+ unsigned FalseReg = getReg(FalseVal, MBB, IP);
+ if (TrueReg == FalseReg) {
+ static const unsigned Opcode[] = {
+ X86::MOV8rr, X86::MOV16rr, X86::MOV32rr, X86::FpMOV, X86::MOV32rr
+ };
+ BuildMI(*MBB, IP, Opcode[SelectClass], 1, DestReg).addReg(TrueReg);
+ if (SelectClass == cLong)
+ BuildMI(*MBB, IP, X86::MOV32rr, 1, DestReg+1).addReg(TrueReg+1);
+ return;
+ }
+
unsigned Opcode;
if (SetCondInst *SCI = canFoldSetCCIntoBranchOrSelect(Cond)) {
// We successfully folded the setcc into the select instruction.
@@ -1130,8 +1141,6 @@
}
}
- unsigned TrueReg = getReg(TrueVal, MBB, IP);
- unsigned FalseReg = getReg(FalseVal, MBB, IP);
unsigned RealDestReg = DestReg;