fix overflow check.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56011 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Devang Patel 2008-09-09 20:54:34 +00:00
parent 0d95267e49
commit 4b3f08bac7
2 changed files with 49 additions and 2 deletions

View File

@ -1551,8 +1551,7 @@ ICmpInst *LoopStrengthReduce::ChangeCompareStride(Loop *L, ICmpInst *Cond,
// Check stride constant and the comparision constant signs to detect
// overflow.
if (ICmpInst::isSignedPredicate(Predicate) &&
(CmpVal & SignBit) != (CmpSSInt & SignBit))
if ((CmpVal & SignBit) != (CmpSSInt & SignBit))
return Cond;
// Look for a suitable stride / iv as replacement.

View File

@ -0,0 +1,48 @@
; RUN: llvm-as < %s | opt -loop-reduce | llvm-dis | grep phi | count 2
; PR 2779
@g_19 = common global i32 0 ; <i32*> [#uses=3]
@"\01LC" = internal constant [4 x i8] c"%d\0A\00" ; <[4 x i8]*> [#uses=1]
define i32 @func_8(i8 zeroext %p_9) nounwind {
entry:
ret i32 1
}
define i32 @func_3(i8 signext %p_5) nounwind {
entry:
ret i32 1
}
define void @func_1() nounwind {
entry:
br label %bb
bb: ; preds = %bb, %entry
%indvar = phi i16 [ 0, %entry ], [ %indvar.next, %bb ] ; <i16> [#uses=2]
%tmp = sub i16 0, %indvar ; <i16> [#uses=1]
%tmp27 = trunc i16 %tmp to i8 ; <i8> [#uses=1]
load i32* @g_19, align 4 ; <i32>:0 [#uses=2]
add i32 %0, 1 ; <i32>:1 [#uses=1]
store i32 %1, i32* @g_19, align 4
trunc i32 %0 to i8 ; <i8>:2 [#uses=1]
tail call i32 @func_8( i8 zeroext %2 ) nounwind ; <i32>:3 [#uses=0]
shl i8 %tmp27, 2 ; <i8>:4 [#uses=1]
add i8 %4, -112 ; <i8>:5 [#uses=1]
tail call i32 @func_3( i8 signext %5 ) nounwind ; <i32>:6 [#uses=0]
%indvar.next = add i16 %indvar, 1 ; <i16> [#uses=2]
%exitcond = icmp eq i16 %indvar.next, -28 ; <i1> [#uses=1]
br i1 %exitcond, label %return, label %bb
return: ; preds = %bb
ret void
}
define i32 @main() nounwind {
entry:
tail call void @func_1( ) nounwind
load i32* @g_19, align 4 ; <i32>:0 [#uses=1]
tail call i32 (i8*, ...)* @printf( i8* getelementptr ([4 x i8]* @"\01LC", i32 0, i32 0), i32 %0 ) nounwind ; <i32>:1 [#uses=0]
ret i32 0
}
declare i32 @printf(i8*, ...) nounwind