[PATCH] D85971: [IndVarSimplify] Fix Modified status for removal of overflow intrinsics

[David Stenberg via Phabricator via llvm-commits]

This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rGe6f332ef1e41: [IndVarSimplify] Fix Modified status for removal of overflow intrinsics (authored by dstenb).

Changed prior to commit:
  https://reviews.llvm.org/D85971?vs=285640&id=294930#toc

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D85971/new/

https://reviews.llvm.org/D85971

Files:
  llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
  llvm/test/Transforms/IndVarSimplify/eliminate-overflow-modified.ll


Index: llvm/test/Transforms/IndVarSimplify/eliminate-overflow-modified.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/IndVarSimplify/eliminate-overflow-modified.ll
@@ -0,0 +1,46 @@
+; RUN: opt < %s -indvars -S -o - | FileCheck %s
+
+; When eliminating the overflow intrinsic the indvars pass would incorrectly
+; return a false Modified status. This was caught by the pass return
+; status check that is hidden under EXPENSIVE_CHECKS.
+
+; CHECK-LABEL: for.body:
+; CHECK-NEXT: %0 = phi i16 [ %1, %for.body ], [ undef, %for.body.preheader ]
+; CHECK-NEXT: %1 = add nsw i16 %0, -1
+; CHECK-NEXT: %cmp = icmp sgt i16 %1, 0
+; CHECK-NEXT:  call void @llvm.assume(i1 %cmp)
+
+; Function Attrs: nounwind
+define void @foo() #0 {
+entry:
+  %cmp1 = icmp sgt i16 undef, 0
+  br i1 %cmp1, label %for.body.preheader, label %for.end
+
+for.body.preheader:                               ; preds = %entry
+  br label %for.body
+
+for.body:                                         ; preds = %for.body.preheader, %for.body
+  %0 = phi i16 [ %2, %for.body ], [ undef, %for.body.preheader ]
+  %1 = call { i16, i1 } @llvm.sadd.with.overflow.i16(i16 %0, i16 -1)
+  %2 = extractvalue { i16, i1 } %1, 0
+  %cmp = icmp sgt i16 %2, 0
+  call void @llvm.assume(i1 %cmp)
+  br label %for.body
+
+for.end:                                          ; preds = %entry
+  ret void
+}
+
+; Function Attrs: nounwind readnone speculatable willreturn
+declare { i16, i1 } @llvm.sadd.with.overflow.i16(i16, i16) #1
+
+; Function Attrs: nounwind willreturn
+declare void @llvm.assume(i1) #2
+
+attributes #0 = { nounwind }
+attributes #1 = { nounwind readnone speculatable willreturn }
+attributes #2 = { nounwind willreturn }
+
+!llvm.ident = !{!0}
+
+!0 = !{!"clang version 12.0.0"}
Index: llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
===================================================================
--- llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
+++ llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
@@ -477,6 +477,7 @@
   if (WO->use_empty())
     WO->eraseFromParent();
 
+  Changed = true;
   return true;
 }
 


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D85971.294930.patch
Type: text/x-patch
Size: 2145 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20200929/263c88ee/attachment.bin>