Teach two-address pass to update the "source" map so it doesn't perform a
non-profitable commute using outdated info. The test case would still fail
because of poor pre-RA schedule. That will be fixed by MI scheduler.
rdar://11472010
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157038 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/TwoAddressInstructionPass.cpp b/lib/CodeGen/TwoAddressInstructionPass.cpp
index e299671..8164690 100644
--- a/lib/CodeGen/TwoAddressInstructionPass.cpp
+++ b/lib/CodeGen/TwoAddressInstructionPass.cpp
@@ -1521,6 +1521,7 @@
#endif
// Emit a copy or rematerialize the definition.
+ bool isCopy = false;
const TargetRegisterClass *rc = MRI->getRegClass(regB);
MachineInstr *DefMI = MRI->getVRegDef(regB);
// If it's safe and profitable, remat the definition instead of
@@ -1537,10 +1538,11 @@
} else {
BuildMI(*mbbi, mi, mi->getDebugLoc(), TII->get(TargetOpcode::COPY),
regA).addReg(regB);
+ isCopy = true;
}
- MachineBasicBlock::iterator prevMI = prior(mi);
// Update DistanceMap.
+ MachineBasicBlock::iterator prevMI = prior(mi);
DistanceMap.insert(std::make_pair(prevMI, Dist));
DistanceMap[mi] = ++Dist;
@@ -1554,6 +1556,10 @@
RemovedKillFlag = true;
}
MO.setReg(regA);
+
+ if (isCopy)
+ // Propagate SrcRegMap.
+ SrcRegMap[regA] = regB;
}
if (AllUsesCopied) {
diff --git a/test/CodeGen/X86/2012-05-17-TwoAddressBug.ll b/test/CodeGen/X86/2012-05-17-TwoAddressBug.ll
new file mode 100644
index 0000000..171c3f1
--- /dev/null
+++ b/test/CodeGen/X86/2012-05-17-TwoAddressBug.ll
@@ -0,0 +1,16 @@
+; RUN: llc < %s -mtriple=x86_64-apple-macosx -pre-RA-sched=source | FileCheck %s
+
+; Teach two-address pass to update the "source" map so it doesn't perform a
+; non-profitable commute using outdated info. The test case would still fail
+; because of poor pre-RA schedule. That will be fixed by MI scheduler.
+; rdar://11472010
+define i32 @t(i32 %mask) nounwind readnone ssp {
+entry:
+; CHECK: t:
+; CHECK-NOT: mov
+ %sub = add i32 %mask, -65535
+ %shr = lshr i32 %sub, 23
+ %and = and i32 %mask, 1
+ %add = add i32 %shr, %and
+ ret i32 %add
+}