[llvm-commits] [llvm] r90269 - in /llvm/trunk: lib/CodeGen/LiveIntervalAnalysis.cpp lib/CodeGen/SimpleRegisterCoalescing.cpp test/CodeGen/X86/2009-12-01-EarlyClobberBug.ll
Evan Cheng
evan.cheng at apple.com
Tue Dec 1 14:25:01 PST 2009
Author: evancheng
Date: Tue Dec 1 16:25:00 2009
New Revision: 90269
URL: http://llvm.org/viewvc/llvm-project?rev=90269&view=rev
Log:
Fix PR5391: support early clobber physical register def tied with a use (ewwww)
- A valno should be set HasRedefByEC if there is an early clobber def in the middle of its live ranges. It should not be set if the def of the valno is defined by an early clobber.
- If a physical register def is tied to an use and it's an early clobber, it just means the HasRedefByEC is set since it's still one continuous live range.
- Add a couple of missing checks for HasRedefByEC in the coalescer. In general, it should not coalesce a vr with a physical register if the physical register has a early clobber def somewhere. This is overly conservative but that's the price for using such a nasty inline asm "feature".
Added:
llvm/trunk/test/CodeGen/X86/2009-12-01-EarlyClobberBug.ll
Modified:
llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp
llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp
Modified: llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp?rev=90269&r1=90268&r2=90269&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp (original)
+++ llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp Tue Dec 1 16:25:00 2009
@@ -374,8 +374,6 @@
// Value#0 is now defined by the 2-addr instruction.
OldValNo->def = RedefIndex;
OldValNo->setCopy(0);
- if (MO.isEarlyClobber())
- OldValNo->setHasRedefByEC(true);
// Add the new live interval which replaces the range for the input copy.
LiveRange LR(DefIndex, RedefIndex, ValNo);
@@ -513,8 +511,6 @@
if (mi->isRegTiedToUseOperand(DefIdx)) {
// Two-address instruction.
end = baseIndex.getDefIndex();
- assert(!mi->getOperand(DefIdx).isEarlyClobber() &&
- "Two address instruction is an early clobber?");
} else {
// Another instruction redefines the register before it is ever read.
// Then the register is essentially dead at the instruction that defines
Modified: llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp?rev=90269&r1=90268&r2=90269&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp (original)
+++ llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp Tue Dec 1 16:25:00 2009
@@ -1938,6 +1938,10 @@
if (Overlaps) {
// If we haven't already recorded that this value # is safe, check it.
if (!InVector(LHSIt->valno, EliminatedLHSVals)) {
+ // If it's re-defined by an early clobber somewhere in the live range,
+ // then conservatively abort coalescing.
+ if (LHSIt->valno->hasRedefByEC())
+ return false;
// Copy from the RHS?
if (!RangeIsDefinedByCopyFromReg(LHS, LHSIt, RHS.reg))
return false; // Nope, bail out.
@@ -1977,6 +1981,10 @@
// if coalescing succeeds. Just skip the liverange.
if (++LHSIt == LHSEnd) break;
} else {
+ // If it's re-defined by an early clobber somewhere in the live range,
+ // then conservatively abort coalescing.
+ if (LHSIt->valno->hasRedefByEC())
+ return false;
// Otherwise, if this is a copy from the RHS, mark it as being merged
// in.
if (RangeIsDefinedByCopyFromReg(LHS, LHSIt, RHS.reg)) {
@@ -2316,6 +2324,10 @@
if (LHSValNoAssignments[I->valno->id] !=
RHSValNoAssignments[J->valno->id])
return false;
+ // If it's re-defined by an early clobber somewhere in the live range,
+ // then conservatively abort coalescing.
+ if (NewVNInfo[LHSValNoAssignments[I->valno->id]]->hasRedefByEC())
+ return false;
}
if (I->end < J->end) {
Added: llvm/trunk/test/CodeGen/X86/2009-12-01-EarlyClobberBug.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/2009-12-01-EarlyClobberBug.ll?rev=90269&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/2009-12-01-EarlyClobberBug.ll (added)
+++ llvm/trunk/test/CodeGen/X86/2009-12-01-EarlyClobberBug.ll Tue Dec 1 16:25:00 2009
@@ -0,0 +1,38 @@
+; RUN: llc < %s -mtriple=x86_64-apple-darwin | FileCheck %s
+; pr5391
+
+define void @t() nounwind ssp {
+entry:
+; CHECK: t:
+; CHECK: movl %ecx, %eax
+; CHECK: %eax = foo (%eax, %ecx)
+ %b = alloca i32 ; <i32*> [#uses=2]
+ %a = alloca i32 ; <i32*> [#uses=1]
+ %"alloca point" = bitcast i32 0 to i32 ; <i32> [#uses=0]
+ %0 = load i32* %b, align 4 ; <i32> [#uses=1]
+ %1 = load i32* %b, align 4 ; <i32> [#uses=1]
+ %asmtmp = call i32 asm "$0 = foo ($1, $2)", "=&{ax},%0,r,~{dirflag},~{fpsr},~{flags}"(i32 %0, i32 %1) nounwind ; <i32> [#uses=1]
+ store i32 %asmtmp, i32* %a
+ br label %return
+
+return: ; preds = %entry
+ ret void
+}
+
+define void @t2() nounwind ssp {
+entry:
+; CHECK: t2:
+; CHECK: movl %eax, %ecx
+; CHECK: %ecx = foo (%ecx, %eax)
+ %b = alloca i32 ; <i32*> [#uses=2]
+ %a = alloca i32 ; <i32*> [#uses=1]
+ %"alloca point" = bitcast i32 0 to i32 ; <i32> [#uses=0]
+ %0 = load i32* %b, align 4 ; <i32> [#uses=1]
+ %1 = load i32* %b, align 4 ; <i32> [#uses=1]
+ %asmtmp = call i32 asm "$0 = foo ($1, $2)", "=&r,%0,r,~{dirflag},~{fpsr},~{flags}"(i32 %0, i32 %1) nounwind ; <i32> [#uses=1]
+ store i32 %asmtmp, i32* %a
+ br label %return
+
+return: ; preds = %entry
+ ret void
+}
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