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Make sure the whole live range is covered when values are pruned twice.

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JoinVals::pruneValues() calls LIS->pruneValue() to avoid conflicts when
overlapping two different values. This produces a set of live range end
points that are used to reconstruct the live range (with SSA update)
after joining the two registers.

When a value is pruned twice, the set of end points was insufficient:

  v1 = DEF
  v1 = REPLACE1
  v1 = REPLACE2
  KILL v1

The end point at KILL would only reconstruct the live range from
REPLACE2 to KILL, leaving the range REPLACE1-REPLACE2 dead.

Add REPLACE2 as an end point in this case so the full live range is
reconstructed.

This fixes PR13999.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165056 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen 2012-10-02 21:46:39 +00:00
parent abe704309f
commit 27cb347d0e
2 changed files with 31 additions and 2 deletions
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6
lib/CodeGen/RegisterCoalescer.cpp
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@ -1733,11 +1733,15 @@ void JoinVals::pruneValues(JoinVals &Other,
// This value takes precedence over the value in Other.LI.
LIS->pruneValue(&Other.LI, Def, &EndPoints);
// Remove <def,read-undef> flags. This def is now a partial redef.
if (!Def.isBlock())
if (!Def.isBlock()) {
for (MIOperands MO(Indexes->getInstructionFromIndex(Def));
MO.isValid(); ++MO)
if (MO->isReg() && MO->isDef() && MO->getReg() == LI.reg)
MO->setIsUndef(false);
// This value will reach instructions below, but we need to make sure
// the live range also reaches the instruction at Def.
EndPoints.push_back(Def);
}
DEBUG(dbgs() << "\t\tpruned " << PrintReg(Other.LI.reg) << " at " << Def
<< ": " << Other.LI << '\n');
break;

27
test/CodeGen/ARM/coalesce-subregs.ll
View File

@ -1,4 +1,4 @@
; RUN: llc < %s -mcpu=cortex-a9 -new-coalescer | FileCheck %s
; RUN: llc < %s -mcpu=cortex-a9 -verify-coalescing | FileCheck %s
target datalayout = "e-p:32:32:32-i1:8:32-i8:8:32-i16:16:32-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:32:64-v128:32:128-a0:0:32-n32-S32"
target triple = "thumbv7-apple-ios0.0.0"
@ -189,3 +189,28 @@ if.end: ; preds = %entry, %if.then
declare <4 x float> @llvm.arm.neon.vld1.v4f32(i8*, i32) nounwind readonly
declare void @llvm.arm.neon.vst1.v4f32(i8*, <4 x float>, i32) nounwind
; CHECK: pr13999
define void @pr13999() nounwind readonly {
entry:
br i1 true, label %outer_loop, label %loop.end
outer_loop:
%d = phi double [ 0.0, %entry ], [ %add, %after_inner_loop ]
%0 = insertelement <2 x double> <double 0.0, double 0.0>, double %d, i32 0
br i1 undef, label %after_inner_loop, label %inner_loop
inner_loop:
br i1 true, label %after_inner_loop, label %inner_loop
after_inner_loop:
%1 = phi <2 x double> [ %0, %outer_loop ], [ <double 0.0, double 0.0>,
%inner_loop ]
%2 = extractelement <2 x double> %1, i32 1
%add = fadd double 1.0, %2
br i1 false, label %loop.end, label %outer_loop
loop.end:
%d.end = phi double [ 0.0, %entry ], [ %add, %after_inner_loop ]
ret void
}