AMDGPU: Don't add same instruction multiple times to worklist

When the instruction is processed the first time, it may be
deleted resulting in crashes. While the new test adds the same
user to the worklist twice, this particular case doesn't crash
but I'm not sure why.

llvm-svn: 290191

diff --git a/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp b/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
index 981b63c..26a8d22 100644 (file)
--- a/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
+++ b/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
@@ -3312,10 +3312,16 @@ void SIInstrInfo::addUsersToMoveToVALUWorklist(
   MachineRegisterInfo &MRI,
   SmallVectorImpl<MachineInstr *> &Worklist) const {
   for (MachineRegisterInfo::use_iterator I = MRI.use_begin(DstReg),
-         E = MRI.use_end(); I != E; ++I) {
+         E = MRI.use_end(); I != E;) {
     MachineInstr &UseMI = *I->getParent();
     if (!canReadVGPR(UseMI, I.getOperandNo())) {
       Worklist.push_back(&UseMI);
+
+      do {
+        ++I;
+      } while (I != E && I->getParent() == &UseMI);
+    } else {
+      ++I;
     }
   }
 }

diff --git a/llvm/test/CodeGen/AMDGPU/sminmax.ll b/llvm/test/CodeGen/AMDGPU/sminmax.ll
index 560d559..8346520 100644 (file)
--- a/llvm/test/CodeGen/AMDGPU/sminmax.ll
+++ b/llvm/test/CodeGen/AMDGPU/sminmax.ll
@@ -32,6 +32,20 @@ define void @v_abs_i32(i32 addrspace(1)* %out, i32 addrspace(1)* %src) nounwind
   ret void
 }
 
+; GCN-LABEL: {{^}}v_abs_i32_repeat_user:
+; GCN: v_sub_i32_e32 [[NEG:v[0-9]+]], vcc, 0, [[SRC:v[0-9]+]]
+; GCN: v_max_i32_e32 [[MAX:v[0-9]+]], [[NEG]], [[SRC]]
+; GCN: v_mul_lo_i32 v{{[0-9]+}}, [[MAX]], [[MAX]]
+define void @v_abs_i32_repeat_user(i32 addrspace(1)* %out, i32 addrspace(1)* %src) nounwind {
+  %val = load i32, i32 addrspace(1)* %src, align 4
+  %neg = sub i32 0, %val
+  %cond = icmp sgt i32 %val, %neg
+  %res = select i1 %cond, i32 %val, i32 %neg
+  %mul = mul i32 %res, %res
+  store i32 %mul, i32 addrspace(1)* %out, align 4
+  ret void
+}
+
 ; FUNC-LABEL: {{^}}s_abs_v2i32:
 ; GCN: s_abs_i32
 ; GCN: s_abs_i32