intel/llvm
1
0
Fork 0
mirror of https://github.com/intel/llvm.git synced 2026-01-27 06:06:34 +08:00
Code Issues Packages Projects Releases Wiki Activity

[ValueTracking] soften assert for invertible recurrence matching

Browse Source 
There's a TODO comment in the code and discussion in D99912
about generalizing this, but I wasn't sure how to implement that,
so just going with a potential minimal fix to avoid crashing.

The test is a reduction beyond useful code (there's no user of
%user...), but it is based on https://llvm.org/PR50191, so this
is asserting on real code.

Differential Revision: https://reviews.llvm.org/D101772
This commit is contained in:
Sanjay Patel
2021-05-03 15:07:10 -04:00
parent fd15e2b825
commit 15a42339fe
2 changed files with 28 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
llvm/lib/Analysis/ValueTracking.cpp
View File

@@ -2608,7 +2608,8 @@ static Optional<unsigned> getInvertibleOperand(const Operator *Op1,
cast<Operator>(BO2));
if (!Idx || *Idx != 0)
break;
assert(BO1->getOperand(*Idx) == PN1 && BO2->getOperand(*Idx) == PN2);
if (BO1->getOperand(*Idx) != PN1 || BO2->getOperand(*Idx) != PN2)
break;
// Phi operands might not be in the same order. TODO: generalize
// interface to return pair of operands.

26
llvm/test/Transforms/InstSimplify/icmp.ll
View File

@@ -187,3 +187,29 @@ define i1 @shl_div_cmp_greater(i8 %x) {
%cmp = icmp ule i8 %div, %x
ret i1 %cmp
}
; Don't crash matching recurrences/invertible ops.
define void @PR50191(i32 %x) {
; CHECK-LABEL: @PR50191(
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[P1:%.*]] = phi i32 [ [[X:%.*]], [[ENTRY:%.*]] ], [ [[SUB1:%.*]], [[LOOP]] ]
; CHECK-NEXT: [[P2:%.*]] = phi i32 [ [[X]], [[ENTRY]] ], [ [[SUB2:%.*]], [[LOOP]] ]
; CHECK-NEXT: [[SUB1]] = sub i32 [[P1]], [[P2]]
; CHECK-NEXT: [[SUB2]] = sub i32 42, [[P2]]
; CHECK-NEXT: br label [[LOOP]]
;
entry:
br label %loop
loop:
%p1 = phi i32 [ %x, %entry ], [ %sub1, %loop ]
%p2 = phi i32 [ %x, %entry ], [ %sub2, %loop ]
%cmp = icmp eq i32 %p1, %p2
%user = zext i1 %cmp to i32
%sub1 = sub i32 %p1, %p2
%sub2 = sub i32 42, %p2
br label %loop
}