[PATCH] D34346: [InstCombine] Make sure AddReachableCodeToWorklist sets MadeIRChange

[Bjorn Pettersson via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rL305725: [InstCombine] Make sure AddReachableCodeToWorklist sets MadeIRChange (authored by bjope).

Changed prior to commit:
  https://reviews.llvm.org/D34346?vs=103015&id=103077#toc

Repository:
  rL LLVM

https://reviews.llvm.org/D34346

Files:
  llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp
  llvm/trunk/test/Transforms/InstCombine/early_constfold_changes_IR.ll
  llvm/trunk/test/Transforms/InstCombine/early_dce_clobbers_callgraph.ll


Index: llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp
===================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -3012,6 +3012,7 @@
         ++NumDeadInst;
         DEBUG(dbgs() << "IC: DCE: " << *Inst << '\n');
         Inst->eraseFromParent();
+        MadeIRChange = true;
         continue;
       }
 
@@ -3025,6 +3026,7 @@
           ++NumConstProp;
           if (isInstructionTriviallyDead(Inst, TLI))
             Inst->eraseFromParent();
+          MadeIRChange = true;
           continue;
         }
 
Index: llvm/trunk/test/Transforms/InstCombine/early_constfold_changes_IR.ll
===================================================================
--- llvm/trunk/test/Transforms/InstCombine/early_constfold_changes_IR.ll
+++ llvm/trunk/test/Transforms/InstCombine/early_constfold_changes_IR.ll
@@ -0,0 +1,20 @@
+; This run line verifies that we get the expected constant fold.
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+; This run line verifies that InstructionCombiningPass::runOnFunction reports
+; this as a modification of the IR.
+; RUN: opt < %s -instcombine -disable-output -debug-pass=Details 2>&1 | FileCheck %s --check-prefix=DETAILS
+
+define i32 @foo(i32 %arg) #0 {
+; CHECK-LABEL: @foo(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[AND:%.*]] = and i32 [[ARG:%.*]], 7
+; CHECK-NEXT:    ret i32 [[AND]]
+;
+entry:
+  %or = or i32 0, 7
+  %and = and i32 %arg, %or
+  ret i32 %and
+}
+
+; DETAILS:  Made Modification 'Combine redundant instructions' on Function 'foo'
Index: llvm/trunk/test/Transforms/InstCombine/early_dce_clobbers_callgraph.ll
===================================================================
--- llvm/trunk/test/Transforms/InstCombine/early_dce_clobbers_callgraph.ll
+++ llvm/trunk/test/Transforms/InstCombine/early_dce_clobbers_callgraph.ll
@@ -0,0 +1,31 @@
+; RUN: opt < %s -inline -instcombine -S | FileCheck %s
+
+; This test case exposed a bug in instcombine where the early
+; DCE of a call wasn't recognized as changing the IR.
+; So when runOnFunction propagated the "made changes" upwards
+; to the CallGraphSCCPass it signalled that no changes had been
+; made, so CallGraphSCCPass assumed that the old CallGraph,
+; as known by that pass manager, still was up-to-date.
+;
+; This was detected as an assert when trying to remove the
+; no longer used function 'bar' (due to incorrect reference
+; count in the CallGraph).
+
+attributes #0 = { noinline norecurse nounwind readnone }
+
+define void @foo() #0 {
+; CHECK-LABEL: @foo(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    ret void
+;
+entry:
+  %call = call i32 @bar()
+  ret void
+}
+
+define internal i32 @bar() #0 {
+; CHECK-NOT: bar
+entry:
+  ret i32 42
+}
+


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