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llvm-mirror/test/Transforms/LoopVectorize/lcssa-crash.ll
Chandler Carruth b3230220b9 [LV] Fix an issue where forming LCSSA in the place that we did would
change the set of uniform instructions in the loop causing an assert
failure.

The problem is that the legalization checking also builds data
structures mapping various facts about the loop body. The immediate
cause was the set of uniform instructions. If these then change when
LCSSA is formed, the data structures would already have been built and
become stale. The included test case triggered an assert in loop
vectorize that was reduced out of the new PM's pipeline.

The solution is to form LCSSA early enough that no information is cached
across the changes made. The only really obvious position is outside of
the main logic to vectorize the loop. This also has the advantage of
removing one case where forming LCSSA could mutate the loop but we
wouldn't track that as a "Changed" state.

If it is significantly advantageous to do some legalization checking
prior to this, we can do a more careful positioning but it seemed best
to just back off to a safe position first.

llvm-svn: 293168
2017-01-26 10:41:09 +00:00

63 lines
1.7 KiB
LLVM

; RUN: opt < %s -loop-vectorize -force-vector-interleave=1 -force-vector-width=4
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-S128"
%type1 = type { %type2 }
%type2 = type { [0 x i8*], i8**, i32, i32, i32 }
define void @test() nounwind uwtable align 2 {
br label %for.body.lr.ph.i.i.i
for.body.lr.ph.i.i.i:
br label %for.body.i.i.i
for.body.i.i.i:
%indvars.iv = phi i64 [ %indvars.iv.next, %for.inc.i.i.i ], [ 0, %for.body.lr.ph.i.i.i ]
br label %for.inc.i.i.i
for.inc.i.i.i:
%indvars.iv.next = add i64 %indvars.iv, 1
%lftr.wideiv = trunc i64 %indvars.iv.next to i32
%exitcond = icmp ne i32 %lftr.wideiv, undef
br i1 %exitcond, label %for.body.i.i.i, label %for.end.i.i.i
for.end.i.i.i:
%lcssa = phi %type1* [ undef, %for.inc.i.i.i ]
unreachable
}
; PR16139
define void @test2(i8* %x) {
entry:
indirectbr i8* %x, [ label %L0, label %L1 ]
L0:
br label %L0
L1:
ret void
}
; This loop has different uniform instructions before and after LCSSA.
define void @test3() {
entry:
%add41 = add i32 undef, undef
%idxprom4736 = zext i32 %add41 to i64
br label %while.body
while.body:
%idxprom4738 = phi i64 [ %idxprom47, %while.body ], [ %idxprom4736, %entry ]
%pos.337 = phi i32 [ %inc46, %while.body ], [ %add41, %entry ]
%inc46 = add i32 %pos.337, 1
%arrayidx48 = getelementptr inbounds [1024 x i8], [1024 x i8]* undef, i64 0, i64 %idxprom4738
store i8 0, i8* %arrayidx48, align 1
%and43 = and i32 %inc46, 3
%cmp44 = icmp eq i32 %and43, 0
%idxprom47 = zext i32 %inc46 to i64
br i1 %cmp44, label %while.end, label %while.body
while.end:
%add58 = add i32 %inc46, 4
ret void
}