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Fix PR4188. TailMerging can't tolerate inexact

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71478 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dale Johannesen 2009-05-11 21:54:13 +00:00
parent fb3bd472a1
commit bf06f6a6f1
2 changed files with 38 additions and 0 deletions
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15
lib/CodeGen/BranchFolding.cpp
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@ -1092,6 +1092,21 @@ void BranchFolder::OptimizeBlock(MachineBasicBlock *MBB) {
} else {
DidChange = true;
PMBB->ReplaceUsesOfBlockWith(MBB, CurTBB);
// If this change resulted in PMBB ending in a conditional
// branch where both conditions go to the same destination,
// change this to an unconditional branch (and fix the CFG).
MachineBasicBlock *NewCurTBB = 0, *NewCurFBB = 0;
SmallVector<MachineOperand, 4> NewCurCond;
bool NewCurUnAnalyzable = TII->AnalyzeBranch(*PMBB, NewCurTBB,
NewCurFBB, NewCurCond, true);
if (!NewCurUnAnalyzable && NewCurTBB && NewCurTBB == NewCurFBB) {
TII->RemoveBranch(*PMBB);
NewCurCond.clear();
TII->InsertBranch(*PMBB, NewCurTBB, 0, NewCurCond);
MadeChange = true;
++NumBranchOpts;
PMBB->CorrectExtraCFGEdges(NewCurTBB, NewCurFBB, false);
}
}
}

23
test/CodeGen/X86/2009-05-11-tailmerge-crash.ll Normal file
View File

@ -0,0 +1,23 @@
; RUN: llvm-as < %s | llc -march=x86
; PR4188
; ModuleID = '<stdin>'
target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
target triple = "i386-apple-darwin9.6"
@g_9 = external global i32 ; <i32*> [#uses=1]
define i32 @int86(i32 %p_87) nounwind {
entry:
%0 = trunc i32 %p_87 to i8 ; <i8> [#uses=1]
%1 = icmp ne i8 %0, 0 ; <i1> [#uses=1]
br label %bb
bb: ; preds = %bb.i, %bb, %entry
%2 = volatile load i32* @g_9, align 4 ; <i32> [#uses=2]
%3 = icmp sgt i32 %2, 1 ; <i1> [#uses=1]
%4 = and i1 %3, %1 ; <i1> [#uses=1]
br i1 %4, label %bb.i, label %bb
bb.i: ; preds = %bb
%5 = icmp sgt i32 0, %2 ; <i1> [#uses=0]
br label %bb
}