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[NFC][LoopIdiom] Add bcmp loop idiom miscompile test from PR43206.

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The transform forgot to check SCEV loop scopes.

https://bugs.llvm.org/show_bug.cgi?id=43206

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@374661 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Roman Lebedev
2019-10-12 15:35:16 +00:00
parent c88bcb8459
commit d31582e52f
1 changed files with 54 additions and 3 deletions
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test/Transforms/LoopIdiom/bcmp-negative-tests.ll
+54 -3
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@@ -1,9 +1,7 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -loop-idiom < %s -S | FileCheck %s
; RUN: opt -loop-idiom -verify -verify-each -verify-dom-info -verify-loop-info < %s -S | FileCheck %s --implicit-check-not=bcmp --implicit-check-not=memcmp
; CHECK: source_filename
; CHECK-NOT; bcmp
; CHECK-NOT; memcmp
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"
@@ -478,3 +476,56 @@ cleanup:
%res = phi i1 [ false, %for.body ], [ true, %for.inc ]
ret i1 %res
}
; See https://bugs.llvm.org/show_bug.cgi?id=43206 for original reduced (but runnable) test:
;
; bool do_check(int i_max, int j_max, int**bptr, int* fillch) {
; for (int i = 0; i < i_max; i++)
; for (int j = 0; j < j_max; j++)
; if (bptr[i][j] != fillch[i])
; return 1;
; return 0;
; }
; The loads proceed differently here - fillch[i] changes once per outer loop,
; while bptr[i][j] changes both in inner loop, and in outer loop.
define i1 @pr43206_different_loops(i32 %i_max, i32 %j_max, i32** %bptr, i32* %fillch) {
entry:
%cmp31 = icmp sgt i32 %i_max, 0
%cmp229 = icmp sgt i32 %j_max, 0
%or.cond = and i1 %cmp31, %cmp229
br i1 %or.cond, label %for.cond1.preheader.us.preheader, label %cleanup12
for.cond1.preheader.us.preheader: ; preds = %entry
%wide.trip.count38 = zext i32 %i_max to i64
%wide.trip.count = zext i32 %j_max to i64
br label %for.cond1.preheader.us
for.cond1.preheader.us: ; preds = %for.cond1.for.inc10_crit_edge.us, %for.cond1.preheader.us.preheader
%indvars.iv36 = phi i64 [ 0, %for.cond1.preheader.us.preheader ], [ %indvars.iv.next37, %for.cond1.for.inc10_crit_edge.us ]
%arrayidx.us = getelementptr inbounds i32*, i32** %bptr, i64 %indvars.iv36
%v0 = load i32*, i32** %arrayidx.us, align 8
%arrayidx8.us = getelementptr inbounds i32, i32* %fillch, i64 %indvars.iv36
%v1 = load i32, i32* %arrayidx8.us, align 4
br label %for.body4.us
for.cond1.us: ; preds = %for.body4.us
%exitcond = icmp eq i64 %indvars.iv.next, %wide.trip.count
br i1 %exitcond, label %for.cond1.for.inc10_crit_edge.us, label %for.body4.us
for.body4.us: ; preds = %for.cond1.us, %for.cond1.preheader.us
%indvars.iv = phi i64 [ 0, %for.cond1.preheader.us ], [ %indvars.iv.next, %for.cond1.us ]
%arrayidx6.us = getelementptr inbounds i32, i32* %v0, i64 %indvars.iv
%v2 = load i32, i32* %arrayidx6.us, align 4
%cmp9.us = icmp eq i32 %v2, %v1
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
br i1 %cmp9.us, label %for.cond1.us, label %cleanup12
for.cond1.for.inc10_crit_edge.us: ; preds = %for.cond1.us
%indvars.iv.next37 = add nuw nsw i64 %indvars.iv36, 1
%exitcond39 = icmp eq i64 %indvars.iv.next37, %wide.trip.count38
br i1 %exitcond39, label %cleanup12, label %for.cond1.preheader.us
cleanup12: ; preds = %for.cond1.for.inc10_crit_edge.us, %for.body4.us, %entry
%v3 = phi i1 [ false, %entry ], [ true, %for.body4.us ], [ false, %for.cond1.for.inc10_crit_edge.us ]
ret i1 %v3
}