[llvm-branch-commits] [llvm] DAG: Call SimplifyDemandedBits on copysign value operand (PR #97180)
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Sat Jun 29 13:25:27 PDT 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-backend-amdgpu
Author: Matt Arsenault (arsenm)
<details>
<summary>Changes</summary>
So far the only cases that seem to benefit are the weird
copysign with different typed inputs.
---
Full diff: https://github.com/llvm/llvm-project/pull/97180.diff
2 Files Affected:
- (modified) llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (+5)
- (modified) llvm/test/CodeGen/AMDGPU/fcopysign.f16.ll (+15-25)
``````````diff
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index eaab2b3421190..5d72b5e1e30dd 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -17571,6 +17571,11 @@ SDValue DAGCombiner::visitFCOPYSIGN(SDNode *N) {
APInt::getSignMask(SignVT.getScalarSizeInBits())))
return SDValue(N, 0);
+ // We only take the non-sign bits from the value operand
+ if (SimplifyDemandedBits(N0,
+ APInt::getSignedMaxValue(VT.getScalarSizeInBits())))
+ return SDValue(N, 0);
+
return SDValue();
}
diff --git a/llvm/test/CodeGen/AMDGPU/fcopysign.f16.ll b/llvm/test/CodeGen/AMDGPU/fcopysign.f16.ll
index b8936911f0576..eda1709e4fd59 100644
--- a/llvm/test/CodeGen/AMDGPU/fcopysign.f16.ll
+++ b/llvm/test/CodeGen/AMDGPU/fcopysign.f16.ll
@@ -1639,10 +1639,7 @@ define amdgpu_kernel void @s_copysign_out_f16_mag_f64_sign_f16(ptr addrspace(1)
; VI-NEXT: v_or_b32_e32 v2, 0x7c00, v2
; VI-NEXT: v_mov_b32_e32 v3, s2
; VI-NEXT: s_cselect_b64 vcc, -1, 0
-; VI-NEXT: s_lshr_b32 s0, s7, 16
; VI-NEXT: v_cndmask_b32_e32 v2, v3, v2, vcc
-; VI-NEXT: s_and_b32 s0, s0, 0x8000
-; VI-NEXT: v_or_b32_e32 v2, s0, v2
; VI-NEXT: s_movk_i32 s0, 0x7fff
; VI-NEXT: v_mov_b32_e32 v3, s8
; VI-NEXT: v_bfi_b32 v2, s0, v2, v3
@@ -1673,36 +1670,33 @@ define amdgpu_kernel void @s_copysign_out_f16_mag_f64_sign_f16(ptr addrspace(1)
; GFX9-NEXT: v_lshlrev_b32_e64 v1, v1, s2
; GFX9-NEXT: v_cmp_ne_u32_e32 vcc, s0, v1
; GFX9-NEXT: v_cndmask_b32_e64 v1, 0, 1, vcc
-; GFX9-NEXT: s_add_i32 s9, s1, 0xfffffc10
+; GFX9-NEXT: s_add_i32 s7, s1, 0xfffffc10
; GFX9-NEXT: v_readfirstlane_b32 s0, v1
-; GFX9-NEXT: s_lshl_b32 s1, s9, 12
+; GFX9-NEXT: s_lshl_b32 s1, s7, 12
; GFX9-NEXT: s_or_b32 s0, s2, s0
; GFX9-NEXT: s_or_b32 s1, s6, s1
-; GFX9-NEXT: s_cmp_lt_i32 s9, 1
-; GFX9-NEXT: s_cselect_b32 s10, s0, s1
-; GFX9-NEXT: s_and_b32 s2, s10, 7
+; GFX9-NEXT: s_cmp_lt_i32 s7, 1
+; GFX9-NEXT: s_cselect_b32 s9, s0, s1
+; GFX9-NEXT: s_and_b32 s2, s9, 7
; GFX9-NEXT: s_cmp_gt_i32 s2, 5
; GFX9-NEXT: s_cselect_b64 s[0:1], -1, 0
; GFX9-NEXT: s_cmp_eq_u32 s2, 3
; GFX9-NEXT: s_cselect_b64 s[2:3], -1, 0
; GFX9-NEXT: s_or_b64 s[0:1], s[2:3], s[0:1]
-; GFX9-NEXT: s_lshr_b32 s2, s10, 2
+; GFX9-NEXT: s_lshr_b32 s2, s9, 2
; GFX9-NEXT: s_cmp_lg_u64 s[0:1], 0
; GFX9-NEXT: s_addc_u32 s0, s2, 0
-; GFX9-NEXT: s_cmp_lt_i32 s9, 31
+; GFX9-NEXT: s_cmp_lt_i32 s7, 31
; GFX9-NEXT: s_cselect_b32 s2, s0, 0x7c00
; GFX9-NEXT: s_cmp_lg_u32 s6, 0
; GFX9-NEXT: s_cselect_b64 s[0:1], -1, 0
; GFX9-NEXT: v_cndmask_b32_e64 v1, 0, 1, s[0:1]
; GFX9-NEXT: v_lshlrev_b32_e32 v1, 9, v1
-; GFX9-NEXT: s_cmpk_eq_i32 s9, 0x40f
+; GFX9-NEXT: s_cmpk_eq_i32 s7, 0x40f
; GFX9-NEXT: v_or_b32_e32 v1, 0x7c00, v1
; GFX9-NEXT: v_mov_b32_e32 v2, s2
; GFX9-NEXT: s_cselect_b64 vcc, -1, 0
-; GFX9-NEXT: s_lshr_b32 s0, s7, 16
; GFX9-NEXT: v_cndmask_b32_e32 v1, v2, v1, vcc
-; GFX9-NEXT: s_and_b32 s0, s0, 0x8000
-; GFX9-NEXT: v_or_b32_e32 v1, s0, v1
; GFX9-NEXT: s_movk_i32 s0, 0x7fff
; GFX9-NEXT: v_mov_b32_e32 v2, s8
; GFX9-NEXT: v_bfi_b32 v1, s0, v1, v2
@@ -1728,13 +1722,13 @@ define amdgpu_kernel void @s_copysign_out_f16_mag_f64_sign_f16(ptr addrspace(1)
; GFX11-NEXT: s_addk_i32 s1, 0xfc10
; GFX11-NEXT: v_med3_i32 v1, s3, 0, 13
; GFX11-NEXT: v_readfirstlane_b32 s3, v0
-; GFX11-NEXT: s_lshl_b32 s8, s1, 12
+; GFX11-NEXT: s_lshl_b32 s7, s1, 12
; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_2) | instskip(NEXT) | instid1(VALU_DEP_2)
; GFX11-NEXT: v_readfirstlane_b32 s6, v1
; GFX11-NEXT: s_or_b32 s2, s2, s3
; GFX11-NEXT: s_delay_alu instid0(SALU_CYCLE_1) | instskip(SKIP_1) | instid1(VALU_DEP_1)
; GFX11-NEXT: s_or_b32 s3, s2, 0x1000
-; GFX11-NEXT: s_or_b32 s8, s2, s8
+; GFX11-NEXT: s_or_b32 s7, s2, s7
; GFX11-NEXT: s_lshr_b32 s6, s3, s6
; GFX11-NEXT: s_delay_alu instid0(SALU_CYCLE_1) | instskip(SKIP_1) | instid1(VALU_DEP_2)
; GFX11-NEXT: v_lshlrev_b32_e64 v0, v1, s6
@@ -1745,15 +1739,15 @@ define amdgpu_kernel void @s_copysign_out_f16_mag_f64_sign_f16(ptr addrspace(1)
; GFX11-NEXT: v_readfirstlane_b32 s3, v0
; GFX11-NEXT: s_or_b32 s3, s6, s3
; GFX11-NEXT: s_cmp_lt_i32 s1, 1
-; GFX11-NEXT: s_cselect_b32 s3, s3, s8
+; GFX11-NEXT: s_cselect_b32 s3, s3, s7
; GFX11-NEXT: s_delay_alu instid0(SALU_CYCLE_1) | instskip(NEXT) | instid1(SALU_CYCLE_1)
; GFX11-NEXT: s_and_b32 s6, s3, 7
; GFX11-NEXT: s_cmp_gt_i32 s6, 5
-; GFX11-NEXT: s_cselect_b32 s8, -1, 0
+; GFX11-NEXT: s_cselect_b32 s7, -1, 0
; GFX11-NEXT: s_cmp_eq_u32 s6, 3
; GFX11-NEXT: s_cselect_b32 s6, -1, 0
; GFX11-NEXT: s_lshr_b32 s3, s3, 2
-; GFX11-NEXT: s_or_b32 s6, s6, s8
+; GFX11-NEXT: s_or_b32 s6, s6, s7
; GFX11-NEXT: s_delay_alu instid0(SALU_CYCLE_1)
; GFX11-NEXT: s_cmp_lg_u32 s6, 0
; GFX11-NEXT: s_addc_u32 s3, s3, 0
@@ -1764,15 +1758,11 @@ define amdgpu_kernel void @s_copysign_out_f16_mag_f64_sign_f16(ptr addrspace(1)
; GFX11-NEXT: s_cmpk_eq_i32 s1, 0x40f
; GFX11-NEXT: v_cndmask_b32_e64 v0, 0, 1, s2
; GFX11-NEXT: s_cselect_b32 vcc_lo, -1, 0
-; GFX11-NEXT: s_lshr_b32 s1, s7, 16
-; GFX11-NEXT: s_delay_alu instid0(SALU_CYCLE_1) | instskip(NEXT) | instid1(VALU_DEP_1)
-; GFX11-NEXT: s_and_b32 s1, s1, 0x8000
-; GFX11-NEXT: v_lshlrev_b32_e32 v0, 9, v0
; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_1) | instskip(NEXT) | instid1(VALU_DEP_1)
+; GFX11-NEXT: v_lshlrev_b32_e32 v0, 9, v0
; GFX11-NEXT: v_or_b32_e32 v0, 0x7c00, v0
-; GFX11-NEXT: v_cndmask_b32_e32 v0, s3, v0, vcc_lo
; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_1) | instskip(NEXT) | instid1(VALU_DEP_1)
-; GFX11-NEXT: v_or_b32_e32 v0, s1, v0
+; GFX11-NEXT: v_cndmask_b32_e32 v0, s3, v0, vcc_lo
; GFX11-NEXT: v_bfi_b32 v0, 0x7fff, v0, s0
; GFX11-NEXT: global_store_b16 v1, v0, s[4:5]
; GFX11-NEXT: s_nop 0
``````````
</details>
https://github.com/llvm/llvm-project/pull/97180
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