Avoid assigning esp (or ebp for framepointer-using frames) in Om1.
For ebp, exclude as needed. For esp, don't mark it as
an int register.
Not sure exactly how to do a targeted test for this Om1
register allocator. The Om1 regalloc seems to start w/ a
fresh whitelist after each instruction, so it may assign
the same register (e.g., eax), as an earlier instruction.
Without pre-colored registers, I'm not sure how to force it
to allocate something other than the first few registers.
I do have a test case that has a ton of pre-colored
registers, (e.g., cmpxchg8b), but that is a different CL:
https://codereview.chromium.org/362463002/
Encountered for:
BUG= https://code.google.com/p/nativeclient/issues/detail?id=3882
R=stichnot@chromium.org
Review URL: https://codereview.chromium.org/369573005
diff --git a/src/IceTargetLoweringX8632.cpp b/src/IceTargetLoweringX8632.cpp
index 7630d37..569fd9e 100644
--- a/src/IceTargetLoweringX8632.cpp
+++ b/src/IceTargetLoweringX8632.cpp
@@ -2569,7 +2569,11 @@
if (Ctx->getOptLevel() != Opt_m1)
return;
// TODO: Avoid recomputing WhiteList every instruction.
- llvm::SmallBitVector WhiteList = getRegisterSet(RegSet_All, RegSet_None);
+ RegSetMask RegInclude = RegSet_All;
+ RegSetMask RegExclude = RegSet_None;
+ if (hasFramePointer())
+ RegExclude |= RegSet_FramePointer;
+ llvm::SmallBitVector WhiteList = getRegisterSet(RegInclude, RegExclude);
// Make one pass to black-list pre-colored registers. TODO: If
// there was some prior register allocation pass that made register
// assignments, those registers need to be black-listed here as
