[AMDGPU] canCreateUndefOrPoisonForTargetNode - BFE_I32/U32 can't create poison/undef (#154932)

Add AMDGPUTargetLowering::canCreateUndefOrPoisonForTargetNode handler
and tag BFE_I32/U32 nodes as they can only propagate poison, not create
poison/undef.

Fighting some of the remaining regressions in #152107

Author: RKSimon

llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp

@@ -6135,6 +6135,19 @@ unsigned AMDGPUTargetLowering::computeNumSignBitsForTargetInstr(
   }
 }
 
+bool AMDGPUTargetLowering::canCreateUndefOrPoisonForTargetNode(
+    SDValue Op, const APInt &DemandedElts, const SelectionDAG &DAG,
+    bool PoisonOnly, bool ConsiderFlags, unsigned Depth) const {
+  unsigned Opcode = Op.getOpcode();
+  switch (Opcode) {
+  case AMDGPUISD::BFE_I32:
+  case AMDGPUISD::BFE_U32:
+    return false;
+  }
+  return TargetLowering::canCreateUndefOrPoisonForTargetNode(
+      Op, DemandedElts, DAG, PoisonOnly, ConsiderFlags, Depth);
+}
+
 bool AMDGPUTargetLowering::isKnownNeverNaNForTargetNode(
     SDValue Op, const APInt &DemandedElts, const SelectionDAG &DAG, bool SNaN,
     unsigned Depth) const {

llvm/lib/Target/AMDGPU/AMDGPUISelLowering.h

@@ -323,6 +323,12 @@ class AMDGPUTargetLowering : public TargetLowering {
                                             const MachineRegisterInfo &MRI,
                                             unsigned Depth = 0) const override;
 
+  bool canCreateUndefOrPoisonForTargetNode(SDValue Op,
+                                           const APInt &DemandedElts,
+                                           const SelectionDAG &DAG,
+                                           bool PoisonOnly, bool ConsiderFlags,
+                                           unsigned Depth) const override;
+
   bool isKnownNeverNaNForTargetNode(SDValue Op, const APInt &DemandedElts,
                                     const SelectionDAG &DAG, bool SNaN = false,
                                     unsigned Depth = 0) const override;

llvm/test/CodeGen/AMDGPU/frem.ll

@@ -1582,28 +1582,22 @@ define amdgpu_kernel void @frem_f64(ptr addrspace(1) %out, ptr addrspace(1) %in1
 ; SI-NEXT:    s_nop 1
 ; SI-NEXT:    v_div_fmas_f64 v[4:5], v[12:13], v[6:7], v[10:11]
 ; SI-NEXT:    v_div_fixup_f64 v[4:5], v[4:5], v[2:3], v[0:1]
-; SI-NEXT:    v_readfirstlane_b32 s2, v5
-; SI-NEXT:    s_bfe_u32 s0, s2, 0xb0014
-; SI-NEXT:    s_add_i32 s3, s0, 0xfffffc01
-; SI-NEXT:    s_mov_b32 s1, 0xfffff
-; SI-NEXT:    s_mov_b32 s0, s6
-; SI-NEXT:    s_lshr_b64 s[0:1], s[0:1], s3
-; SI-NEXT:    v_not_b32_e32 v6, s0
-; SI-NEXT:    v_and_b32_e32 v6, v4, v6
-; SI-NEXT:    v_not_b32_e32 v7, s1
-; SI-NEXT:    v_and_b32_e32 v5, v5, v7
-; SI-NEXT:    s_and_b32 s0, s2, 0x80000000
-; SI-NEXT:    s_cmp_lt_i32 s3, 0
-; SI-NEXT:    s_cselect_b64 vcc, -1, 0
-; SI-NEXT:    v_cndmask_b32_e64 v6, v6, 0, vcc
-; SI-NEXT:    v_mov_b32_e32 v7, s0
-; SI-NEXT:    v_cndmask_b32_e32 v5, v5, v7, vcc
-; SI-NEXT:    s_cmp_gt_i32 s3, 51
-; SI-NEXT:    s_cselect_b64 vcc, -1, 0
-; SI-NEXT:    v_mov_b32_e32 v7, s2
-; SI-NEXT:    v_cndmask_b32_e32 v5, v5, v7, vcc
-; SI-NEXT:    v_cndmask_b32_e32 v4, v6, v4, vcc
-; SI-NEXT:    v_fma_f64 v[0:1], -v[4:5], v[2:3], v[0:1]
+; SI-NEXT:    v_readfirstlane_b32 s0, v4
+; SI-NEXT:    v_readfirstlane_b32 s1, v5
+; SI-NEXT:    s_bfe_u32 s2, s1, 0xb0014
+; SI-NEXT:    s_add_i32 s8, s2, 0xfffffc01
+; SI-NEXT:    s_mov_b32 s3, 0xfffff
+; SI-NEXT:    s_mov_b32 s2, s6
+; SI-NEXT:    s_lshr_b64 s[2:3], s[2:3], s8
+; SI-NEXT:    s_andn2_b64 s[2:3], s[0:1], s[2:3]
+; SI-NEXT:    s_and_b32 s9, s1, 0x80000000
+; SI-NEXT:    s_cmp_lt_i32 s8, 0
+; SI-NEXT:    s_cselect_b32 s2, 0, s2
+; SI-NEXT:    s_cselect_b32 s3, s9, s3
+; SI-NEXT:    s_cmp_gt_i32 s8, 51
+; SI-NEXT:    s_cselect_b32 s1, s1, s3
+; SI-NEXT:    s_cselect_b32 s0, s0, s2
+; SI-NEXT:    v_fma_f64 v[0:1], -s[0:1], v[2:3], v[0:1]
 ; SI-NEXT:    buffer_store_dwordx2 v[0:1], off, s[4:7], 0
 ; SI-NEXT:    s_endpgm
 ;
@@ -1859,28 +1853,22 @@ define amdgpu_kernel void @fast_frem_f64(ptr addrspace(1) %out, ptr addrspace(1)
 ; SI-NEXT:    v_mul_f64 v[6:7], v[0:1], v[4:5]
 ; SI-NEXT:    v_fma_f64 v[8:9], -v[2:3], v[6:7], v[0:1]
 ; SI-NEXT:    v_fma_f64 v[4:5], v[8:9], v[4:5], v[6:7]
-; SI-NEXT:    v_readfirstlane_b32 s6, v5
-; SI-NEXT:    s_bfe_u32 s4, s6, 0xb0014
-; SI-NEXT:    s_add_i32 s7, s4, 0xfffffc01
-; SI-NEXT:    s_mov_b32 s5, 0xfffff
-; SI-NEXT:    s_mov_b32 s4, s2
-; SI-NEXT:    s_lshr_b64 s[4:5], s[4:5], s7
-; SI-NEXT:    v_not_b32_e32 v6, s4
-; SI-NEXT:    v_and_b32_e32 v6, v4, v6
-; SI-NEXT:    v_not_b32_e32 v7, s5
-; SI-NEXT:    v_and_b32_e32 v5, v5, v7
-; SI-NEXT:    s_and_b32 s4, s6, 0x80000000
-; SI-NEXT:    s_cmp_lt_i32 s7, 0
-; SI-NEXT:    s_cselect_b64 vcc, -1, 0
-; SI-NEXT:    v_cndmask_b32_e64 v6, v6, 0, vcc
-; SI-NEXT:    v_mov_b32_e32 v7, s4
-; SI-NEXT:    v_cndmask_b32_e32 v5, v5, v7, vcc
-; SI-NEXT:    s_cmp_gt_i32 s7, 51
-; SI-NEXT:    s_cselect_b64 vcc, -1, 0
-; SI-NEXT:    v_mov_b32_e32 v7, s6
-; SI-NEXT:    v_cndmask_b32_e32 v5, v5, v7, vcc
-; SI-NEXT:    v_cndmask_b32_e32 v4, v6, v4, vcc
-; SI-NEXT:    v_fma_f64 v[0:1], -v[4:5], v[2:3], v[0:1]
+; SI-NEXT:    v_readfirstlane_b32 s4, v4
+; SI-NEXT:    v_readfirstlane_b32 s5, v5
+; SI-NEXT:    s_bfe_u32 s6, s5, 0xb0014
+; SI-NEXT:    s_add_i32 s8, s6, 0xfffffc01
+; SI-NEXT:    s_mov_b32 s7, 0xfffff
+; SI-NEXT:    s_mov_b32 s6, s2
+; SI-NEXT:    s_lshr_b64 s[6:7], s[6:7], s8
+; SI-NEXT:    s_andn2_b64 s[6:7], s[4:5], s[6:7]
+; SI-NEXT:    s_and_b32 s9, s5, 0x80000000
+; SI-NEXT:    s_cmp_lt_i32 s8, 0
+; SI-NEXT:    s_cselect_b32 s6, 0, s6
+; SI-NEXT:    s_cselect_b32 s7, s9, s7
+; SI-NEXT:    s_cmp_gt_i32 s8, 51
+; SI-NEXT:    s_cselect_b32 s5, s5, s7
+; SI-NEXT:    s_cselect_b32 s4, s4, s6
+; SI-NEXT:    v_fma_f64 v[0:1], -s[4:5], v[2:3], v[0:1]
 ; SI-NEXT:    buffer_store_dwordx2 v[0:1], off, s[0:3], 0
 ; SI-NEXT:    s_endpgm
 ;
@@ -2109,28 +2097,22 @@ define amdgpu_kernel void @unsafe_frem_f64(ptr addrspace(1) %out, ptr addrspace(
 ; SI-NEXT:    v_mul_f64 v[6:7], v[0:1], v[4:5]
 ; SI-NEXT:    v_fma_f64 v[8:9], -v[2:3], v[6:7], v[0:1]
 ; SI-NEXT:    v_fma_f64 v[4:5], v[8:9], v[4:5], v[6:7]
-; SI-NEXT:    v_readfirstlane_b32 s6, v5
-; SI-NEXT:    s_bfe_u32 s4, s6, 0xb0014
-; SI-NEXT:    s_add_i32 s7, s4, 0xfffffc01
-; SI-NEXT:    s_mov_b32 s5, 0xfffff
-; SI-NEXT:    s_mov_b32 s4, s2
-; SI-NEXT:    s_lshr_b64 s[4:5], s[4:5], s7
-; SI-NEXT:    v_not_b32_e32 v6, s4
-; SI-NEXT:    v_and_b32_e32 v6, v4, v6
-; SI-NEXT:    v_not_b32_e32 v7, s5
-; SI-NEXT:    v_and_b32_e32 v5, v5, v7
-; SI-NEXT:    s_and_b32 s4, s6, 0x80000000
-; SI-NEXT:    s_cmp_lt_i32 s7, 0
-; SI-NEXT:    s_cselect_b64 vcc, -1, 0
-; SI-NEXT:    v_cndmask_b32_e64 v6, v6, 0, vcc
-; SI-NEXT:    v_mov_b32_e32 v7, s4
-; SI-NEXT:    v_cndmask_b32_e32 v5, v5, v7, vcc
-; SI-NEXT:    s_cmp_gt_i32 s7, 51
-; SI-NEXT:    s_cselect_b64 vcc, -1, 0
-; SI-NEXT:    v_mov_b32_e32 v7, s6
-; SI-NEXT:    v_cndmask_b32_e32 v5, v5, v7, vcc
-; SI-NEXT:    v_cndmask_b32_e32 v4, v6, v4, vcc
-; SI-NEXT:    v_fma_f64 v[0:1], -v[4:5], v[2:3], v[0:1]
+; SI-NEXT:    v_readfirstlane_b32 s4, v4
+; SI-NEXT:    v_readfirstlane_b32 s5, v5
+; SI-NEXT:    s_bfe_u32 s6, s5, 0xb0014
+; SI-NEXT:    s_add_i32 s8, s6, 0xfffffc01
+; SI-NEXT:    s_mov_b32 s7, 0xfffff
+; SI-NEXT:    s_mov_b32 s6, s2
+; SI-NEXT:    s_lshr_b64 s[6:7], s[6:7], s8
+; SI-NEXT:    s_andn2_b64 s[6:7], s[4:5], s[6:7]
+; SI-NEXT:    s_and_b32 s9, s5, 0x80000000
+; SI-NEXT:    s_cmp_lt_i32 s8, 0
+; SI-NEXT:    s_cselect_b32 s6, 0, s6
+; SI-NEXT:    s_cselect_b32 s7, s9, s7
+; SI-NEXT:    s_cmp_gt_i32 s8, 51
+; SI-NEXT:    s_cselect_b32 s5, s5, s7
+; SI-NEXT:    s_cselect_b32 s4, s4, s6
+; SI-NEXT:    v_fma_f64 v[0:1], -s[4:5], v[2:3], v[0:1]
 ; SI-NEXT:    buffer_store_dwordx2 v[0:1], off, s[0:3], 0
 ; SI-NEXT:    s_endpgm
 ;
@@ -5251,27 +5233,22 @@ define amdgpu_kernel void @frem_v2f64(ptr addrspace(1) %out, ptr addrspace(1) %i
 ; SI-NEXT:    s_nop 1
 ; SI-NEXT:    v_div_fmas_f64 v[8:9], v[16:17], v[10:11], v[14:15]
 ; SI-NEXT:    v_div_fixup_f64 v[8:9], v[8:9], v[6:7], v[2:3]
-; SI-NEXT:    v_readfirstlane_b32 s8, v9
-; SI-NEXT:    s_bfe_u32 s0, s8, 0xb0014
-; SI-NEXT:    s_add_i32 s9, s0, 0xfffffc01
+; SI-NEXT:    v_readfirstlane_b32 s0, v8
+; SI-NEXT:    v_readfirstlane_b32 s1, v9
+; SI-NEXT:    s_bfe_u32 s2, s1, 0xb0014
+; SI-NEXT:    s_add_i32 s10, s2, 0xfffffc01
 ; SI-NEXT:    s_mov_b32 s3, 0xfffff
-; SI-NEXT:    s_lshr_b64 s[0:1], s[2:3], s9
-; SI-NEXT:    v_not_b32_e32 v10, s0
-; SI-NEXT:    v_and_b32_e32 v10, v8, v10
-; SI-NEXT:    v_not_b32_e32 v11, s1
-; SI-NEXT:    v_and_b32_e32 v9, v9, v11
-; SI-NEXT:    s_and_b32 s0, s8, 0x80000000
-; SI-NEXT:    s_cmp_lt_i32 s9, 0
-; SI-NEXT:    s_cselect_b64 vcc, -1, 0
-; SI-NEXT:    v_cndmask_b32_e64 v10, v10, 0, vcc
-; SI-NEXT:    v_mov_b32_e32 v11, s0
-; SI-NEXT:    v_cndmask_b32_e32 v9, v9, v11, vcc
-; SI-NEXT:    s_cmp_gt_i32 s9, 51
-; SI-NEXT:    s_cselect_b64 vcc, -1, 0
-; SI-NEXT:    v_mov_b32_e32 v11, s8
-; SI-NEXT:    v_cndmask_b32_e32 v9, v9, v11, vcc
-; SI-NEXT:    v_cndmask_b32_e32 v8, v10, v8, vcc
-; SI-NEXT:    v_fma_f64 v[2:3], -v[8:9], v[6:7], v[2:3]
+; SI-NEXT:    s_mov_b32 s2, s6
+; SI-NEXT:    s_lshr_b64 s[8:9], s[2:3], s10
+; SI-NEXT:    s_andn2_b64 s[8:9], s[0:1], s[8:9]
+; SI-NEXT:    s_and_b32 s11, s1, 0x80000000
+; SI-NEXT:    s_cmp_lt_i32 s10, 0
+; SI-NEXT:    s_cselect_b32 s8, 0, s8
+; SI-NEXT:    s_cselect_b32 s9, s11, s9
+; SI-NEXT:    s_cmp_gt_i32 s10, 51
+; SI-NEXT:    s_cselect_b32 s1, s1, s9
+; SI-NEXT:    s_cselect_b32 s0, s0, s8
+; SI-NEXT:    v_fma_f64 v[2:3], -s[0:1], v[6:7], v[2:3]
 ; SI-NEXT:    v_div_scale_f64 v[6:7], s[0:1], v[4:5], v[4:5], v[0:1]
 ; SI-NEXT:    v_rcp_f64_e32 v[8:9], v[6:7]
 ; SI-NEXT:    v_fma_f64 v[10:11], -v[6:7], v[8:9], 1.0
@@ -5287,26 +5264,20 @@ define amdgpu_kernel void @frem_v2f64(ptr addrspace(1) %out, ptr addrspace(1) %i
 ; SI-NEXT:    s_nop 1
 ; SI-NEXT:    v_div_fmas_f64 v[6:7], v[14:15], v[8:9], v[12:13]
 ; SI-NEXT:    v_div_fixup_f64 v[6:7], v[6:7], v[4:5], v[0:1]
-; SI-NEXT:    v_readfirstlane_b32 s8, v7
-; SI-NEXT:    s_bfe_u32 s0, s8, 0xb0014
-; SI-NEXT:    s_add_i32 s9, s0, 0xfffffc01
-; SI-NEXT:    s_lshr_b64 s[0:1], s[2:3], s9
-; SI-NEXT:    v_not_b32_e32 v8, s0
-; SI-NEXT:    v_and_b32_e32 v8, v6, v8
-; SI-NEXT:    v_not_b32_e32 v9, s1
-; SI-NEXT:    v_and_b32_e32 v7, v7, v9
-; SI-NEXT:    s_and_b32 s0, s8, 0x80000000
-; SI-NEXT:    s_cmp_lt_i32 s9, 0
-; SI-NEXT:    s_cselect_b64 vcc, -1, 0
-; SI-NEXT:    v_cndmask_b32_e64 v8, v8, 0, vcc
-; SI-NEXT:    v_mov_b32_e32 v9, s0
-; SI-NEXT:    v_cndmask_b32_e32 v7, v7, v9, vcc
-; SI-NEXT:    s_cmp_gt_i32 s9, 51
-; SI-NEXT:    s_cselect_b64 vcc, -1, 0
-; SI-NEXT:    v_mov_b32_e32 v9, s8
-; SI-NEXT:    v_cndmask_b32_e32 v7, v7, v9, vcc
-; SI-NEXT:    v_cndmask_b32_e32 v6, v8, v6, vcc
-; SI-NEXT:    v_fma_f64 v[0:1], -v[6:7], v[4:5], v[0:1]
+; SI-NEXT:    v_readfirstlane_b32 s0, v6
+; SI-NEXT:    v_readfirstlane_b32 s1, v7
+; SI-NEXT:    s_bfe_u32 s8, s1, 0xb0014
+; SI-NEXT:    s_addk_i32 s8, 0xfc01
+; SI-NEXT:    s_lshr_b64 s[2:3], s[2:3], s8
+; SI-NEXT:    s_andn2_b64 s[2:3], s[0:1], s[2:3]
+; SI-NEXT:    s_and_b32 s9, s1, 0x80000000
+; SI-NEXT:    s_cmp_lt_i32 s8, 0
+; SI-NEXT:    s_cselect_b32 s2, 0, s2
+; SI-NEXT:    s_cselect_b32 s3, s9, s3
+; SI-NEXT:    s_cmp_gt_i32 s8, 51
+; SI-NEXT:    s_cselect_b32 s1, s1, s3
+; SI-NEXT:    s_cselect_b32 s0, s0, s2
+; SI-NEXT:    v_fma_f64 v[0:1], -s[0:1], v[4:5], v[0:1]
 ; SI-NEXT:    buffer_store_dwordx4 v[0:3], off, s[4:7], 0
 ; SI-NEXT:    s_endpgm
 ;

llvm/test/CodeGen/AMDGPU/llvm.round.f64.ll

@@ -76,12 +76,13 @@ define amdgpu_kernel void @v_round_f64(ptr addrspace(1) %out, ptr addrspace(1) %
 ; SI-NEXT:    s_waitcnt lgkmcnt(0)
 ; SI-NEXT:    s_mov_b64 s[4:5], s[2:3]
 ; SI-NEXT:    buffer_load_dwordx2 v[2:3], v[0:1], s[4:7], 0 addr64
+; SI-NEXT:    s_movk_i32 s4, 0xfc01
 ; SI-NEXT:    s_mov_b32 s2, -1
 ; SI-NEXT:    s_mov_b32 s3, 0xfffff
 ; SI-NEXT:    v_mov_b32_e32 v8, 0x3ff00000
 ; SI-NEXT:    s_waitcnt vmcnt(0)
 ; SI-NEXT:    v_bfe_u32 v4, v3, 20, 11
-; SI-NEXT:    v_add_i32_e32 v6, vcc, 0xfffffc01, v4
+; SI-NEXT:    v_add_i32_e32 v6, vcc, s4, v4
 ; SI-NEXT:    v_lshr_b64 v[4:5], s[2:3], v6
 ; SI-NEXT:    v_and_b32_e32 v7, 0x80000000, v3
 ; SI-NEXT:    v_not_b32_e32 v5, v5