[PATCH] D15859: [InstructionCombining] prepareICWorklistFromFunction halts in infinite loop with instructions of token type

[Chen Li via llvm-commits]

chenli created this revision.
chenli added a reviewer: majnemer.
chenli added a subscriber: llvm-commits.
Herald added a subscriber: sanjoy.

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.

http://reviews.llvm.org/D15859

Files:
  lib/Transforms/InstCombine/InstructionCombining.cpp
  test/Transforms/InstCombine/token.ll

Index: test/Transforms/InstCombine/token.ll
===================================================================
--- test/Transforms/InstCombine/token.ll
+++ test/Transforms/InstCombine/token.ll
@@ -85,5 +85,22 @@
 ; 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)
Index: lib/Transforms/InstCombine/InstructionCombining.cpp
===================================================================
--- lib/Transforms/InstCombine/InstructionCombining.cpp
+++ lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -3021,16 +3021,15 @@
       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;
       }
       if (!isa<DbgInfoIntrinsic>(Inst)) {
         ++NumDeadInst;
         MadeIRChange = true;
       }
-      if (!Inst->getType()->isTokenTy())
-        Inst->eraseFromParent();
+      Inst->eraseFromParent();
     }
   }
 


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