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Handle single-entry phi nodes gracefully in condprop.

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llvm-svn: 62985
This commit is contained in:
Chris Lattner 2009-01-26 02:18:20 +00:00
parent 5549fb4e74
commit f93b292d9b
2 changed files with 45 additions and 0 deletions
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8
lib/Transforms/Scalar/CondPropagate.cpp
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@ -126,6 +126,14 @@ void CondProp::SimplifyPredecessors(BranchInst *BI) {
// one use (the branch), and is the only instruction besides the branch in the
// block.
PHINode *PN = cast<PHINode>(BI->getCondition());
if (PN->getNumIncomingValues() == 1) {
// Eliminate single-entry PHI nodes.
FoldSingleEntryPHINodes(PN->getParent());
return;
}
if (!PN->hasOneUse()) return;
BasicBlock *BB = BI->getParent();

37
test/Transforms/CondProp/2009-01-25-SingleEntryPHI.ll Normal file
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@ -0,0 +1,37 @@
; RUN: llvm-as < %s | opt -condprop | llvm-dis
; PR3405
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"
target triple = "x86_64-unknown-linux-gnu"
define i32 @main(i32 %argc, i8** %argv) nounwind {
entry:
br label %bb2
bb2: ; preds = %bb.bb2_crit_edge, %entry
br i1 false, label %bb5.thread2, label %bb
bb: ; preds = %bb2
br i1 false, label %bb3, label %bb.bb2_crit_edge
bb.bb2_crit_edge: ; preds = %bb
br label %bb2
bb3: ; preds = %bb
%.lcssa4 = phi i1 [ false, %bb ] ; <i1> [#uses=1]
br i1 %.lcssa4, label %bb5.thread, label %bb6
bb5.thread: ; preds = %bb3
br label %bb7
bb7: ; preds = %bb5.thread2, %bb5.thread
br label %UnifiedReturnBlock
bb6: ; preds = %bb3
br label %UnifiedReturnBlock
bb5.thread2: ; preds = %bb2
br label %bb7
UnifiedReturnBlock: ; preds = %bb6, %bb7
ret i32 0
}