[PATCH] D15035: AMDGPU/SI: Prevent the DAGCombiner from creating setcc with i1 inputs

[Tom Stellard via llvm-commits]

tstellarAMD created this revision.
tstellarAMD added a reviewer: arsenm.
tstellarAMD added a subscriber: llvm-commits.
Herald added a subscriber: arsenm.

http://reviews.llvm.org/D15035

Files:
  lib/Target/AMDGPU/SIISelLowering.cpp
  lib/Target/AMDGPU/SIISelLowering.h
  test/CodeGen/AMDGPU/setcc.ll
  test/CodeGen/AMDGPU/trunc-cmp-constant.ll

Index: test/CodeGen/AMDGPU/trunc-cmp-constant.ll
===================================================================
--- test/CodeGen/AMDGPU/trunc-cmp-constant.ll
+++ test/CodeGen/AMDGPU/trunc-cmp-constant.ll
@@ -4,8 +4,7 @@
 ; FUNC-LABEL {{^}}sextload_i1_to_i32_trunc_cmp_eq_0:
 ; SI: buffer_load_ubyte [[LOAD:v[0-9]+]]
 ; SI: v_and_b32_e32 [[TMP:v[0-9]+]], 1, [[LOAD]]
-; SI: v_cmp_eq_i32_e32 vcc, 1, [[TMP]]{{$}}
-; SI: s_xor_b64 s{{\[[0-9]+:[0-9]+\]}}, vcc, -1{{$}}
+; SI: v_cmp_eq_i32_e32 vcc, 0, [[TMP]]{{$}}
 ; SI: v_cndmask_b32_e64
 ; SI: buffer_store_byte
 define void @sextload_i1_to_i32_trunc_cmp_eq_0(i1 addrspace(1)* %out, i1 addrspace(1)* %in) nounwind {
Index: test/CodeGen/AMDGPU/setcc.ll
===================================================================
--- test/CodeGen/AMDGPU/setcc.ll
+++ test/CodeGen/AMDGPU/setcc.ll
@@ -375,3 +375,17 @@
   store <3 x i8> %ext, <3 x i8> addrspace(1)* %gep.out
   ret void
 }
+
+; Make sure we don't try to emit i1 setcc ops
+; FUNC-LABEL: setcc-i1
+; SI: s_and_b32 [[AND:s[0-9]+]], s{{[0-9]+}}, 1
+; SI: v_cmp_eq_i32_e64 s[0:1], 0, [[AND]]
+define void @setcc-i1(i32 %in) {
+  %and = and i32 %in, 1
+  %cmp = icmp eq i32 %and, 0
+  br i1 %cmp, label %endif, label %if
+if:
+  unreachable
+endif:
+  ret void
+}
Index: lib/Target/AMDGPU/SIISelLowering.h
===================================================================
--- lib/Target/AMDGPU/SIISelLowering.h
+++ lib/Target/AMDGPU/SIISelLowering.h
@@ -83,6 +83,8 @@
   bool shouldConvertConstantLoadToIntImm(const APInt &Imm,
                                         Type *Ty) const override;
 
+  bool isTypeDesirableForOp(unsigned Op, EVT VT) const override;
+
   SDValue LowerFormalArguments(SDValue Chain, CallingConv::ID CallConv,
                                bool isVarArg,
                                const SmallVectorImpl<ISD::InputArg> &Ins,
Index: lib/Target/AMDGPU/SIISelLowering.cpp
===================================================================
--- lib/Target/AMDGPU/SIISelLowering.cpp
+++ lib/Target/AMDGPU/SIISelLowering.cpp
@@ -507,6 +507,17 @@
   return TII->isInlineConstant(Imm);
 }
 
+bool SITargetLowering::isTypeDesirableForOp(unsigned Op, EVT VT) const {
+
+  // SimplifySetCC uses this function to determine whether or not it should
+  // create setcc with i1 operands.  We don't want i1 setcc or really any i1
+  // operations.
+  if (VT == MVT::i1)
+    return false;
+
+  return TargetLowering::isTypeDesirableForOp(Op, VT);
+}
+
 SDValue SITargetLowering::LowerParameter(SelectionDAG &DAG, EVT VT, EVT MemVT,
                                          SDLoc SL, SDValue Chain,
                                          unsigned Offset, bool Signed) const {


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