When inserting code into a loop preheader, insert it before the

terminator, instead of after the last phi. This fixes a bug
exposed by ScalarEvolution analyzing more kinds of loops.
This fixes PR4436.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74072 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2009-06-24 14:31:06 +00:00
parent cd58c5940c
commit 32a81a3f6d
2 changed files with 67 additions and 3 deletions

View File

@ -230,13 +230,16 @@ void IndVarSimplify::RewriteLoopExitValues(Loop *L,
// We insert the code into the preheader of the loop if the loop contains
// multiple exit blocks, or in the exit block if there is exactly one.
BasicBlock *BlockToInsertInto;
BasicBlock::iterator InsertPt;
SmallVector<BasicBlock*, 8> ExitBlocks;
L->getUniqueExitBlocks(ExitBlocks);
if (ExitBlocks.size() == 1)
if (ExitBlocks.size() == 1) {
BlockToInsertInto = ExitBlocks[0];
else
InsertPt = BlockToInsertInto->getFirstNonPHI();
} else {
BlockToInsertInto = Preheader;
BasicBlock::iterator InsertPt = BlockToInsertInto->getFirstNonPHI();
InsertPt = BlockToInsertInto->getTerminator();
}
std::map<Instruction*, Value*> ExitValues;

View File

@ -0,0 +1,61 @@
; RUN: llvm-as < %s | opt -indvars
; PR4436
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-f80:32:32"
target triple = "i386-pc-linux-gnu"
define i8* @string_expandtabs() nounwind {
entry:
br i1 undef, label %bb33, label %bb1
bb1: ; preds = %entry
br i1 undef, label %overflow1, label %bb15
bb15: ; preds = %bb1
br i1 undef, label %bb33, label %bb17
bb17: ; preds = %bb15
br label %bb30
bb19: ; preds = %bb30
br i1 undef, label %bb20, label %bb29
bb20: ; preds = %bb19
%0 = load i32* undef, align 4 ; <i32> [#uses=1]
%1 = sub i32 %0, undef ; <i32> [#uses=1]
br label %bb23
bb21: ; preds = %bb23
%2 = icmp ult i8* %q.0, undef ; <i1> [#uses=1]
br i1 %2, label %bb22, label %overflow2
bb22: ; preds = %bb21
%3 = getelementptr i8* %q.0, i32 1 ; <i8*> [#uses=1]
br label %bb23
bb23: ; preds = %bb22, %bb20
%i.2 = phi i32 [ %1, %bb20 ], [ %4, %bb22 ] ; <i32> [#uses=1]
%q.0 = phi i8* [ undef, %bb20 ], [ %3, %bb22 ] ; <i8*> [#uses=3]
%4 = add i32 %i.2, -1 ; <i32> [#uses=2]
%5 = icmp eq i32 %4, -1 ; <i1> [#uses=1]
br i1 %5, label %bb29, label %bb21
bb29: ; preds = %bb23, %bb19
%q.1 = phi i8* [ undef, %bb19 ], [ %q.0, %bb23 ] ; <i8*> [#uses=0]
br label %bb30
bb30: ; preds = %bb29, %bb17
br i1 undef, label %bb19, label %bb33
overflow2: ; preds = %bb21
br i1 undef, label %bb32, label %overflow1
bb32: ; preds = %overflow2
br label %overflow1
overflow1: ; preds = %bb32, %overflow2, %bb1
ret i8* null
bb33: ; preds = %bb30, %bb15, %entry
ret i8* undef
}