Add option to force filetype=asm for testing

src/IceTargetLoweringX8632Traits.h

Index: src/IceTargetLoweringX8632Traits.h
diff --git a/src/IceTargetLoweringX8632Traits.h b/src/IceTargetLoweringX8632Traits.h
index 2010ee45152aae6eb4b9ad5103240c847ad5f7c8..0b33634b8275bd484554491825da61ca9571bd2a 100644
--- a/src/IceTargetLoweringX8632Traits.h
+++ b/src/IceTargetLoweringX8632Traits.h
@@ -364,6 +364,17 @@ struct TargetX8632Traits {
     assert(RegNum != Variable::NoRegister);
     // TODO(stichnot): Rewrite this as a table lookup from a table computed in a
     // TargetLowering static initializer.
+    // [abcd]h registers are not convertible to their ?l, ?x, and e?x versions.
+    switch (RegNum) {
+    default:
+      break;
+    case RegisterSet::Reg_ah:
+    case RegisterSet::Reg_bh:
+    case RegisterSet::Reg_ch:
+    case RegisterSet::Reg_dh:
+      assert(Ty == IceType_i8 || Ty == IceType_i1);

[Jim Stichnoth, 2016/01/10 03:08:56]

assert(isByteSizedType(Ty));

(looks like there are a few other places in the code base that could use this
change...)

[sehr, 2016/01/11 21:49:48]

Done.

+      return RegNum;
+    }
     RegNum = getBaseReg(RegNum);
     if (Ty == IceType_i8 || Ty == IceType_i1) {
       switch (RegNum) {