[llvm-commits] CVS: llvm/lib/Target/X86/InstSelectSimple.cpp

[Chris Lattner]

Changes in directory llvm/lib/Target/X86:

InstSelectSimple.cpp updated: 1.235 -> 1.236

---
Log message:

Implement a small optimization, which papers over the problem in
X86/2004-04-13-FPCMOV-Crash.llx

A more robust fix is to follow.



---
Diffs of the changes:  (+12 -3)

Index: llvm/lib/Target/X86/InstSelectSimple.cpp
diff -u llvm/lib/Target/X86/InstSelectSimple.cpp:1.235 llvm/lib/Target/X86/InstSelectSimple.cpp:1.236
--- llvm/lib/Target/X86/InstSelectSimple.cpp:1.235	Tue Apr 13 12:20:37 2004
+++ llvm/lib/Target/X86/InstSelectSimple.cpp	Tue Apr 13 16:56:09 2004
@@ -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;