[InstructionCombining] prepareICWorklistFromFunction halts in infinite loop with...

Summary: This patch fixes a bug in prepareICWorklistFromFunction, where the loop becomes infinite with instructions of token type. The patch checks if the instruction is token type, and if so it updates EndInst with the current instruction.

Reviewers: reames, majnemer

Subscribers: llvm-commits, sanjoy

Differential Revision: http://reviews.llvm.org/D15859

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@256792 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/InstCombine/InstructionCombining.cpp b/lib/Transforms/InstCombine/InstructionCombining.cpp
index 7c46cfd..903a0b5 100644 (file)
--- a/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -3021,7 +3021,7 @@ static bool prepareICWorklistFromFunction(Function &F, const DataLayout &DL,
       Instruction *Inst = &*--EndInst->getIterator();
       if (!Inst->use_empty() && !Inst->getType()->isTokenTy())
         Inst->replaceAllUsesWith(UndefValue::get(Inst->getType()));
-      if (Inst->isEHPad()) {
+      if (Inst->isEHPad() || Inst->getType()->isTokenTy()) {
         EndInst = Inst;
         continue;
       }
@@ -3029,8 +3029,7 @@ static bool prepareICWorklistFromFunction(Function &F, const DataLayout &DL,
         ++NumDeadInst;
         MadeIRChange = true;
       }
-      if (!Inst->getType()->isTokenTy())
-        Inst->eraseFromParent();
+      Inst->eraseFromParent();
     }
   }
 

diff --git a/test/Transforms/InstCombine/token.ll b/test/Transforms/InstCombine/token.ll
index 0929cf7..f96b85b 100644 (file)
--- a/test/Transforms/InstCombine/token.ll
+++ b/test/Transforms/InstCombine/token.ll
@@ -85,5 +85,22 @@ unreachable:
 ; CHECK:  %Y = zext i8 %B to i32
 ; CHECK:  %phi = phi i32 [ %X, %bb ], [ %Y, %cont ], [ %Y, %cont2 ]
 
+declare void @foo()
+declare token @llvm.experimental.gc.statepoint.p0f_isVoidf(i64, i32, void ()*, i32, i32, ...)
+
+define void @test4(i8 addrspace(1)* %obj) gc "statepoint-example" {
+bb:
+  unreachable
+
+unreachable:
+  call token (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @foo, i32 0, i32 0, i32 0, i32 5, i32 0, i32 -1, i32 0, i32 0, i32 0)
+  ret void
+}
+
+; CHECK-LABEL: define void @test4(
+; CHECK: unreachable:
+; CHECK:   call token (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @foo, i32 0, i32 0, i32 0, i32 5, i32 0, i32 -1, i32 0, i32 0, i32 0)
+; CHECK:   ret void
+
 
 declare void @g(i32)