-anders-aa and -gvn marks values as undefined incorrectly

[edwintorok]

Bugzilla Link	2299
Resolution	LATER
Resolved on	Nov 22, 2009 07:47
Version	unspecified
OS	Linux
Attachments	testcase, C code, preprocessed source code
CC	@asl

Extended Description

Using SVN r50866, opt -ander-aa -gvn marks some values as undefined, but that is not correct:

This portion of IR:
%buf2 = bitcast [8 x i32]* %buf12 to i8* ; <i8*> [#uses=1]
%tmp4 = call i64 @​fread( i8* noalias %buf2, i64 32, i64 1, %struct.FILE* noalias %tmp1 ) nounwind ; [#uses=0]
%tmp7 = load i32* %buf12.sub, align 4 ; [#uses=1]
%tmp9 = malloc i8, i32 %tmp7 ; <i8*> [#uses=1]

Gets turned into:

    %buf2 = bitcast [8 x i32]* %buf12 to i8*                ; <i8*> [#uses=1]
    %tmp4 = call i64 @&#8203;fread( i8* noalias  %buf2, i64 32, i64 1, %struct.FILE* noalias  %tmp1 ) nounwind             ; <i64> [#uses=0]
    %tmp9 = malloc i8, i32 undef            ; <i8*> [#uses=1]

To reproduce:
../../../Debug/bin/opt -anders-aa -gvn z.bc -o -|llvm-dis

-basic-aa works, does it get confused by the noalias mark?
FWIW the original C code had no aliases:
...
fread(buf,sizeof(buf),1,f);
use( malloc((int)buf) );
...

[edwintorok]

Created an attachment (id=1622) [details]
testcase

Using SVN r50866, opt -ander-aa -gvn marks some values as undefined, but that
is not correct:

opt -anders-aa -gvn

-basic-aa works, does it get confused by the noalias mark?

I mean -basicaa

[lattner]

andersaa is experimental, it isn't worth tracking individual bugs for it.