[llvm] 10ab29e - [IRCE] Bail out if AddRec in icmp is for another loop (PR58912)

[Dmitry Makogon via llvm-commits]

Author: Dmitry Makogon
Date: 2022-11-14T15:06:13+07:00
New Revision: 10ab29ec6eaf3ee0a70574b4cb6f79a4df01d47d

URL: https://github.com/llvm/llvm-project/commit/10ab29ec6eaf3ee0a70574b4cb6f79a4df01d47d
DIFF: https://github.com/llvm/llvm-project/commit/10ab29ec6eaf3ee0a70574b4cb6f79a4df01d47d.diff

LOG: [IRCE] Bail out if AddRec in icmp is for another loop (PR58912)

When IRCE runs on outer loop and sees a check of an AddRec of
inner loop, it crashes with an assert in SCEV that the AddRec
must be loop invariant.
This adds a bail out if the AddRec which is checked in icmp
is for another loop.

Fixes https://github.com/llvm/llvm-project/issues/58912.

Differential Revision: https://reviews.llvm.org/D137822

Added: 
    

Modified: 
    llvm/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp
    llvm/test/Transforms/IRCE/iv-for-another-loop.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp b/llvm/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp
index e429aafc896ed..15a0e938c8ea1 100644
--- a/llvm/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp
@@ -845,6 +845,10 @@ LoopStructure::parseLoopStructure(ScalarEvolution &SE, Loop &L,
   // induction variable satisfies some constraint.
 
   const SCEVAddRecExpr *IndVarBase = cast<SCEVAddRecExpr>(LeftSCEV);
+  if (IndVarBase->getLoop() != &L) {
+    FailureReason = "LHS in cmp is not an AddRec for this loop";
+    return None;
+  }
   if (!IndVarBase->isAffine()) {
     FailureReason = "LHS in icmp not induction variable";
     return None;

diff  --git a/llvm/test/Transforms/IRCE/iv-for-another-loop.ll b/llvm/test/Transforms/IRCE/iv-for-another-loop.ll
index e4fba0a90f7e9..4b69844c16859 100644
--- a/llvm/test/Transforms/IRCE/iv-for-another-loop.ll
+++ b/llvm/test/Transforms/IRCE/iv-for-another-loop.ll
@@ -1,12 +1,40 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt -S -irce -irce-print-changed-loops=true < %s | FileCheck %s
+; RUN: opt -S -passes=irce -irce-print-changed-loops=true < %s | FileCheck %s
 
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128-ni:1-p2:32:8:8:32-ni:2"
 target triple = "x86_64-unknown-linux-gnu"
 
 ; REQUIRES: asserts
-; XFAIL: *
 
 define void @test() {
+; CHECK-LABEL: @test(
+; CHECK-NEXT:  bb:
+; CHECK-NEXT:    br label [[OUTER_HEADER:%.*]]
+; CHECK:       outer_latch:
+; CHECK-NEXT:    [[TMP:%.*]] = or i32 [[TMP5:%.*]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = add nuw nsw i32 [[TMP5]], 1
+; CHECK-NEXT:    [[TMP3:%.*]] = icmp eq i32 [[TMP8:%.*]], 0
+; CHECK-NEXT:    br i1 [[TMP3]], label [[RET2:%.*]], label [[OUTER_HEADER]]
+; CHECK:       outer_header:
+; CHECK-NEXT:    [[TMP5]] = phi i32 [ 0, [[BB:%.*]] ], [ [[TMP2]], [[OUTER_LATCH:%.*]] ]
+; CHECK-NEXT:    br label [[INNER_HEADER:%.*]]
+; CHECK:       inner_exit:
+; CHECK-NEXT:    [[TMP12_LCSSA:%.*]] = phi i32 [ [[TMP12:%.*]], [[INNER_HEADER]] ]
+; CHECK-NEXT:    [[TMP7:%.*]] = or i32 [[TMP12_LCSSA]], [[TMP5]]
+; CHECK-NEXT:    [[TMP8]] = add nuw i32 [[TMP12_LCSSA]], [[TMP5]]
+; CHECK-NEXT:    [[TMP9:%.*]] = icmp ult i32 [[TMP5]], 0
+; CHECK-NEXT:    br i1 [[TMP9]], label [[OUTER_LATCH]], label [[RET1:%.*]]
+; CHECK:       ret1:
+; CHECK-NEXT:    ret void
+; CHECK:       inner_header:
+; CHECK-NEXT:    [[TMP12]] = phi i32 [ [[TMP14:%.*]], [[INNER_HEADER]] ], [ 0, [[OUTER_HEADER]] ]
+; CHECK-NEXT:    [[TMP13:%.*]] = or i32 [[TMP12]], 1
+; CHECK-NEXT:    [[TMP14]] = add nuw nsw i32 [[TMP12]], 1
+; CHECK-NEXT:    br i1 true, label [[INNER_EXIT:%.*]], label [[INNER_HEADER]]
+; CHECK:       ret2:
+; CHECK-NEXT:    ret void
+;
 bb:
   br label %outer_header