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llvm-project/llvm/test/CodeGen/AMDGPU/bit-op-reduce-width-known-bits.ll
Matt Arsenault 80064b6e32
AMDGPU: Try constant fold after folding immediate (#141862) 
This helps avoid some regressions in a future patch. The or 0
pattern appears in the division tests because the reduce 64-bit
bit operation to a 32-bit one with half identity value is only
implemented for constants. We could fix that by using computeKnownBits.
Additionally the pattern disappears if I optimize the IR division
expansion, so that IR should probably be emitted more optimally in
the first place.
2025-06-10 11:44:44 +09:00

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; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
; RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx900 < %s | FileCheck %s
; Check for situations where we could reduce the width of bitwise
; operations.
; Should be able to reduce this to a 32-bit or plus a copy
; https://alive2.llvm.org/ce/z/9LddFX
define i64 @v_xor_i64_known_hi_i32_from_arg_range(i64 range(i64 0, 4294967296) %arg0, i64 %arg1) {
; CHECK-LABEL: v_xor_i64_known_hi_i32_from_arg_range:
; CHECK: ; %bb.0:
; CHECK-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
; CHECK-NEXT: v_xor_b32_e32 v1, v1, v3
; CHECK-NEXT: v_xor_b32_e32 v0, v0, v2
; CHECK-NEXT: s_setpc_b64 s[30:31]
%xor = xor i64 %arg0, %arg1
ret i64 %xor
}
; Should be able to reduce this to a 32-bit or plus a copy
; https://alive2.llvm.org/ce/z/HaXnBJ
define i64 @v_or_i64_known_hi_i32_from_arg_range(i64 range(i64 0, 4294967296) %arg0, i64 %arg1) {
; CHECK-LABEL: v_or_i64_known_hi_i32_from_arg_range:
; CHECK: ; %bb.0:
; CHECK-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
; CHECK-NEXT: v_or_b32_e32 v1, v1, v3
; CHECK-NEXT: v_or_b32_e32 v0, v0, v2
; CHECK-NEXT: s_setpc_b64 s[30:31]
%or = or i64 %arg0, %arg1
ret i64 %or
}
; https://alive2.llvm.org/ce/z/M96Ror
; Should be able to reduce this to a 32-bit plus a copy
define i64 @v_and_i64_known_i32_from_arg_range(i64 range(i64 -4294967296, 0) %arg0, i64 %arg1) {
; CHECK-LABEL: v_and_i64_known_i32_from_arg_range:
; CHECK: ; %bb.0:
; CHECK-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
; CHECK-NEXT: v_and_b32_e32 v1, v1, v3
; CHECK-NEXT: v_and_b32_e32 v0, v0, v2
; CHECK-NEXT: s_setpc_b64 s[30:31]
%and = and i64 %arg0, %arg1
ret i64 %and
}
define i64 @s_xor_i64_known_i32_from_arg_range(i64 range(i64 0, 65) inreg %arg) {
; CHECK-LABEL: s_xor_i64_known_i32_from_arg_range:
; CHECK: ; %bb.0:
; CHECK-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
; CHECK-NEXT: s_not_b64 s[4:5], s[16:17]
; CHECK-NEXT: v_mov_b32_e32 v0, s4
; CHECK-NEXT: v_mov_b32_e32 v1, s5
; CHECK-NEXT: s_setpc_b64 s[30:31]
%xor = xor i64 %arg, -1
ret i64 %xor
}
define i64 @v_xor_i64_known_i32_from_call_range() {
; CHECK-LABEL: v_xor_i64_known_i32_from_call_range:
; CHECK: ; %bb.0:
; CHECK-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
; CHECK-NEXT: ;;#ASMSTART
; CHECK-NEXT: ; def v[0:1]
; CHECK-NEXT: ;;#ASMEND
; CHECK-NEXT: v_not_b32_e32 v1, v1
; CHECK-NEXT: v_not_b32_e32 v0, v0
; CHECK-NEXT: s_setpc_b64 s[30:31]
%call = call range(i64 0, 65) i64 asm "; def $0", "=v"()
%xor = xor i64 %call, -1
ret i64 %xor
}
define i64 @s_xor_i64_known_i32_from_call_range() {
; CHECK-LABEL: s_xor_i64_known_i32_from_call_range:
; CHECK: ; %bb.0:
; CHECK-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
; CHECK-NEXT: ;;#ASMSTART
; CHECK-NEXT: ; def s[4:5]
; CHECK-NEXT: ;;#ASMEND
; CHECK-NEXT: s_not_b64 s[4:5], s[4:5]
; CHECK-NEXT: v_mov_b32_e32 v0, s4
; CHECK-NEXT: v_mov_b32_e32 v1, s5
; CHECK-NEXT: s_setpc_b64 s[30:31]
%call = call range(i64 0, 65) i64 asm "; def $0", "=s"()
%xor = xor i64 %call, -1
ret i64 %xor
}
; Reduced from -amdgpu-codegenprepare-expand-div64 output, produces a
; not of 0 which ideally would fold out.
; FIXME: Produces not of constant 0
define i64 @v_xor_i64_known_i32_from_range_use_out_of_block(i64 %x) {
; CHECK-LABEL: v_xor_i64_known_i32_from_range_use_out_of_block:
; CHECK: ; %bb.0: ; %entry
; CHECK-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
; CHECK-NEXT: v_ffbh_u32_e32 v2, v0
; CHECK-NEXT: v_add_u32_e32 v2, 32, v2
; CHECK-NEXT: v_ffbh_u32_e32 v3, v1
; CHECK-NEXT: v_min_u32_e32 v4, v2, v3
; CHECK-NEXT: v_mov_b32_e32 v5, 0
; CHECK-NEXT: v_cmp_eq_u64_e32 vcc, v[4:5], v[0:1]
; CHECK-NEXT: v_mov_b32_e32 v2, 0
; CHECK-NEXT: v_mov_b32_e32 v3, 0
; CHECK-NEXT: s_and_saveexec_b64 s[4:5], vcc
; CHECK-NEXT: ; %bb.1: ; %inc
; CHECK-NEXT: v_not_b32_e32 v2, v4
; CHECK-NEXT: v_add_co_u32_e32 v2, vcc, v0, v2
; CHECK-NEXT: v_addc_co_u32_e32 v3, vcc, -1, v1, vcc
; CHECK-NEXT: ; %bb.2: ; %UnifiedReturnBlock
; CHECK-NEXT: s_or_b64 exec, exec, s[4:5]
; CHECK-NEXT: v_mov_b32_e32 v0, v2
; CHECK-NEXT: v_mov_b32_e32 v1, v3
; CHECK-NEXT: s_setpc_b64 s[30:31]
entry:
%ctlz = tail call range(i64 0, 65) i64 @llvm.ctlz.i64(i64 %x, i1 true)
%cmp.entry.not = icmp eq i64 %ctlz, %x
br i1 %cmp.entry.not, label %inc, label %ret
inc: ; preds = %entry
%i1 = xor i64 %ctlz, -1
%i2 = add i64 %x, %i1
ret i64 %i2
ret: ; preds = %loop, %entry
ret i64 0
}
define i64 @s_xor_i64_known_i32_from_range_use_out_of_block(i64 inreg %x) {
; CHECK-LABEL: s_xor_i64_known_i32_from_range_use_out_of_block:
; CHECK: ; %bb.0: ; %entry
; CHECK-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
; CHECK-NEXT: s_flbit_i32_b64 s4, s[16:17]
; CHECK-NEXT: s_mov_b32 s5, 0
; CHECK-NEXT: s_cmp_lg_u64 s[4:5], s[16:17]
; CHECK-NEXT: s_cbranch_scc1 .LBB7_2
; CHECK-NEXT: ; %bb.1: ; %inc
; CHECK-NEXT: s_not_b64 s[4:5], s[4:5]
; CHECK-NEXT: s_add_u32 s4, s16, s4
; CHECK-NEXT: s_addc_u32 s5, s17, s5
; CHECK-NEXT: v_mov_b32_e32 v0, s4
; CHECK-NEXT: v_mov_b32_e32 v1, s5
; CHECK-NEXT: s_setpc_b64 s[30:31]
; CHECK-NEXT: .LBB7_2: ; %ret
; CHECK-NEXT: v_mov_b32_e32 v0, 0
; CHECK-NEXT: v_mov_b32_e32 v1, 0
; CHECK-NEXT: s_setpc_b64 s[30:31]
entry:
%ctlz = tail call range(i64 0, 65) i64 @llvm.ctlz.i64(i64 %x, i1 true)
%cmp.entry.not = icmp eq i64 %ctlz, %x
br i1 %cmp.entry.not, label %inc, label %ret
inc: ; preds = %entry
%i1 = xor i64 %ctlz, -1
%i2 = add i64 %x, %i1
ret i64 %i2
ret: ; preds = %loop, %entry
ret i64 0
}
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