Legalize div/idiv operands to avoid immediates.

src/IceTargetLoweringX8632.cpp

Index: src/IceTargetLoweringX8632.cpp
diff --git a/src/IceTargetLoweringX8632.cpp b/src/IceTargetLoweringX8632.cpp
index 46a587fe1f139727438baf153e72f350b3945311..2942352a22a821db3d1e90a030cad8c42bd25427 100644
--- a/src/IceTargetLoweringX8632.cpp
+++ b/src/IceTargetLoweringX8632.cpp
@@ -1136,6 +1136,7 @@ void TargetX8632::lowerArithmetic(const InstArithmetic *Inst) {
       _mov(Dest, T);
       break;
     case InstArithmetic::Udiv:
+      Src1 = legalize(Src1, Legal_Reg | Legal_Mem, true);

[Jim Stichnoth, 2014/06/17 05:35:06]

It's hard to wrap my head around the AllowOverlap logic in legalize(), but I'm
pretty sure its value will be ignored if Legal_Mem is set and RegNum is not
specified.  Assuming this is true, it would be better to leave AllowOverlap to
be the default false value.  Here and below.  (Of course, the example this was
copied from is probably "wrong" as well...)

[jvoung (off chromium), 2014/06/17 16:11:08]

Done. Yeah it looks like it will be ignored in this case, where Legal_Mem is set
and RegNum is not specified. Changed to default arguments.

       if (Dest->getType() == IceType_i8) {
         Variable *T_ah = NULL;
         Constant *Zero = Ctx->getConstantInt(IceType_i8, 0);
@@ -1152,6 +1153,7 @@ void TargetX8632::lowerArithmetic(const InstArithmetic *Inst) {
       }
       break;
     case InstArithmetic::Sdiv:
+      Src1 = legalize(Src1, Legal_Reg | Legal_Mem, true);
       T_edx = makeReg(IceType_i32, Reg_edx);
       _mov(T, Src0, Reg_eax);
       _cdq(T_edx, T);
@@ -1159,6 +1161,7 @@ void TargetX8632::lowerArithmetic(const InstArithmetic *Inst) {
       _mov(Dest, T);
       break;
     case InstArithmetic::Urem:
+      Src1 = legalize(Src1, Legal_Reg | Legal_Mem, true);
       if (Dest->getType() == IceType_i8) {
         Variable *T_ah = NULL;
         Constant *Zero = Ctx->getConstantInt(IceType_i8, 0);
@@ -1175,6 +1178,7 @@ void TargetX8632::lowerArithmetic(const InstArithmetic *Inst) {
       }
       break;
     case InstArithmetic::Srem:
+      Src1 = legalize(Src1, Legal_Reg | Legal_Mem, true);
       T_edx = makeReg(IceType_i32, Reg_edx);
       _mov(T, Src0, Reg_eax);
       _cdq(T_edx, T);