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Make jump threading honor x|undef -> true and x&undef -> false, 

instead of considering x|undef -> x, which may not be true.

llvm-svn: 95850
This commit is contained in:
Chris Lattner 2010-02-11 04:40:44 +00:00
parent aeea8ac3d8
commit d924f63692
2 changed files with 77 additions and 3 deletions
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11
llvm/lib/Transforms/Scalar/JumpThreading.cpp
View File

@ -336,13 +336,18 @@ ComputeValueKnownInPredecessors(Value *V, BasicBlock *BB,PredValueInfo &Result){
else
InterestingVal = ConstantInt::getFalse(I->getContext());
// Scan for the sentinel.
// Scan for the sentinel. If we find an undef, force it to the
// interesting value: x|undef -> true and x&undef -> false.
for (unsigned i = 0, e = LHSVals.size(); i != e; ++i)
if (LHSVals[i].first == InterestingVal || LHSVals[i].first == 0)
if (LHSVals[i].first == InterestingVal || LHSVals[i].first == 0) {
Result.push_back(LHSVals[i]);
Result.back().first = InterestingVal;
}
for (unsigned i = 0, e = RHSVals.size(); i != e; ++i)
if (RHSVals[i].first == InterestingVal || RHSVals[i].first == 0)
if (RHSVals[i].first == InterestingVal || RHSVals[i].first == 0) {
Result.push_back(RHSVals[i]);
Result.back().first = InterestingVal;
}
return !Result.empty();
}

69
llvm/test/Transforms/JumpThreading/or-undef.ll Normal file
View File

@ -0,0 +1,69 @@
; RUN: opt -jump-threading -S %s | FileCheck %s
; rdar://7620633
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
target triple = "x86_64-apple-darwin11.0"
define void @test1(i8* %args, i32 %from_tty) nounwind optsize ssp {
entry:
%tmp = call i8* @f3(void (i8*)* null, i8* null) nounwind ; <i8*> [#uses=1]
%tmp1 = icmp eq i8* %args, null ; <i1> [#uses=1]
br i1 %tmp1, label %bb2, label %bb
; CHECK: entry:
; CHECK-NEXT: %tmp = call i8* @f3
; CHECK-NEXT: %tmp1 = icmp eq i8* %args, null
; CHECK-NEXT: br i1 %tmp1, label %bb7, label %bb
bb: ; preds = %entry
%tmp2 = call noalias i8** @buildargv(i8* %args) nounwind ; <i8**> [#uses=4]
%tmp3 = icmp eq i8** %tmp2, null ; <i1> [#uses=1]
br i1 %tmp3, label %bb2, label %bb1
bb1: ; preds = %bb
call void @f2(i8** %tmp2) nounwind
br label %bb2
bb2: ; preds = %bb1, %bb, %entry
%argv.0 = phi i8** [ %tmp2, %bb1 ], [ %tmp2, %bb ], [ undef, %entry ] ; <i8**> [#uses=4]
%tmp5 = icmp eq i8* %args, null ; <i1> [#uses=1]
%tmp6 = icmp eq i8** %argv.0, null ; <i1> [#uses=1]
%tmp7 = or i1 %tmp5, %tmp6 ; <i1> [#uses=1]
br i1 %tmp7, label %bb7, label %bb5
bb5: ; preds = %bb2
%tmp8 = load i8** %argv.0, align 8 ; <i8*> [#uses=1]
%tmp9 = icmp eq i8* %tmp8, null ; <i1> [#uses=1]
br i1 %tmp9, label %bb7, label %bb6
bb6: ; preds = %bb5
%tmp10 = load i8** %argv.0, align 8 ; <i8*> [#uses=1]
%tmp11 = load i8* %tmp10, align 1 ; <i8> [#uses=1]
%tmp12 = icmp eq i8 %tmp11, 0 ; <i1> [#uses=1]
br i1 %tmp12, label %bb7, label %bb8
bb7: ; preds = %bb6, %bb5, %bb2
call void @f1() nounwind optsize ssp
br label %bb9
bb8: ; preds = %bb6
%tmp13 = load i8** %argv.0, align 8 ; <i8*> [#uses=1]
%tmp14 = call i64 @f5(i8* %tmp13) nounwind ; <i64> [#uses=0]
br label %bb9
bb9: ; preds = %bb8, %bb7
call void @f4(i8* %tmp) nounwind
ret void
}
declare noalias i8** @buildargv(i8*)
declare void @f2(i8**)
declare void @f4(i8*)
declare i8* @f3(void (i8*)*, i8*)
declare void @f1()
declare i64 @f5(i8*)