Subzero: Fix lowering for x86 div/rem instructions.

src/IceTargetLoweringX86BaseImpl.h

Index: src/IceTargetLoweringX86BaseImpl.h
diff --git a/src/IceTargetLoweringX86BaseImpl.h b/src/IceTargetLoweringX86BaseImpl.h
index 435332bbef78b3c474ec461a2d94a0472f73e45d..bcbc3ced817194c64689b8d51b0559c8d517c881 100644
--- a/src/IceTargetLoweringX86BaseImpl.h
+++ b/src/IceTargetLoweringX86BaseImpl.h
@@ -2283,7 +2283,9 @@ void TargetX86Base<TraitsType>::lowerArithmetic(const InstArithmetic *Instr) {
     T_edx = makeReg(Ty, Edx);
     _mov(T, Src0, Eax);
     _mov(T_edx, Ctx->getConstantZero(Ty));
-    _div(T, Src1, T_edx);
+    _div(T_edx, Src1, T);
+    Context.insert<InstFakeDef>(T, T_edx);
+    _set_dest_redefined();
     _mov(Dest, T);
   } break;
   case InstArithmetic::Sdiv:
@@ -2343,7 +2345,9 @@ void TargetX86Base<TraitsType>::lowerArithmetic(const InstArithmetic *Instr) {
       break;
     }
     _cbwdq(T_edx, T);
-    _idiv(T, Src1, T_edx);
+    _idiv(T_edx, Src1, T);
+    Context.insert<InstFakeDef>(T, T_edx);

[John, 2016/07/19 03:18:19]

can you use the _redefined method here?

_redefined(Context.insert<InstFakeDef>(T, T_edx))

[Jim Stichnoth, 2016/07/19 13:35:35]

Done.

+    _set_dest_redefined();
     _mov(Dest, T);
     break;
   case InstArithmetic::Urem: {
@@ -2373,7 +2377,9 @@ void TargetX86Base<TraitsType>::lowerArithmetic(const InstArithmetic *Instr) {
     T_edx = makeReg(Ty, Edx);
     _mov(T_edx, Ctx->getConstantZero(Ty));
     _mov(T, Src0, Eax);
-    _div(T_edx, Src1, T);
+    _div(T, Src1, T_edx);
+    Context.insert<InstFakeDef>(T_edx, T);
+    _set_dest_redefined();
     if (Ty == IceType_i8) {
       // Register ah must be moved into one of {al,bl,cl,dl} before it can be
       // moved into a general 8-bit register.
@@ -2450,7 +2456,9 @@ void TargetX86Base<TraitsType>::lowerArithmetic(const InstArithmetic *Instr) {
     T_edx = makeReg(Ty, Edx);
     _mov(T, Src0, Eax);
     _cbwdq(T_edx, T);
-    _idiv(T_edx, Src1, T);
+    _idiv(T, Src1, T_edx);
+    Context.insert<InstFakeDef>(T_edx, T);
+    _set_dest_redefined();
     if (Ty == IceType_i8) {
       // Register ah must be moved into one of {al,bl,cl,dl} before it can be
       // moved into a general 8-bit register.