[PATCH] D6629: x86: Emit LAHF/SAHF instead of PUSHF/POPF

[JF Bastien]

jfb added inline comments.

================
Comment at: lib/Target/X86/X86InstrInfo.cpp:3940
@@ +3939,3 @@
+    if (!AXDead)
+      BuildMI(MBB, MI, DL, get(Push)).addReg(AX, getKillRegState(true));
+    if (FromEFLAGS) {
----------------
rnk wrote:
> I'm concerned that we don't have the right kill states here and below. Unfortunately, I don't know enough to say what we should be doing. :(
Sciencedog here: how would I test this? Push it to do the wrong thing?


http://reviews.llvm.org/D6629