ca1154d1d4
It is not correct to lower "x<<32-y>>32-y" to "bfe x, 0, y". When y equals to 32, the left-hand side is still x (unchanged), however, the right-hand side will be evaluated to 0. So it is not always correct to do such transformation. We may be able to keep the pattern for immediate y while y is within [0, 31]. However, the immediate operands of the sub (32 - y) are easily folded, and "(x << imm) >> imm" will be lowered to "and x, (2^(32-imm))-1" anyway. So no bfe matching is needed.
196 lines
6.6 KiB
LLVM
196 lines
6.6 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
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; RUN: llc -mtriple=amdgcn-- -verify-machineinstrs < %s | FileCheck -check-prefix=GCN -check-prefix=SI %s
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; RUN: llc -mtriple=amdgcn-- -mcpu=tonga -verify-machineinstrs < %s | FileCheck -check-prefix=GCN -check-prefix=VI %s
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; Loosely based on test/CodeGen/{X86,AArch64}/extract-lowbits.ll,
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; but with all 64-bit tests, and tests with loads dropped.
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; Patterns:
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; a) x & (1 << nbits) - 1
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; b) x & ~(-1 << nbits)
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; c) x & (-1 >> (32 - y))
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; d) x << (32 - y) >> (32 - y)
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; are equivalent.
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; ---------------------------------------------------------------------------- ;
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; Pattern a. 32-bit
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; ---------------------------------------------------------------------------- ;
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define i32 @bzhi32_a0(i32 %val, i32 %numlowbits) nounwind {
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; GCN-LABEL: bzhi32_a0:
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; GCN: ; %bb.0:
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; GCN-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
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; GCN-NEXT: v_bfe_u32 v0, v0, 0, v1
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; GCN-NEXT: s_setpc_b64 s[30:31]
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%onebit = shl i32 1, %numlowbits
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%mask = add nsw i32 %onebit, -1
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%masked = and i32 %mask, %val
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ret i32 %masked
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}
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define i32 @bzhi32_a1_indexzext(i32 %val, i8 zeroext %numlowbits) nounwind {
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; GCN-LABEL: bzhi32_a1_indexzext:
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; GCN: ; %bb.0:
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; GCN-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
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; GCN-NEXT: v_bfe_u32 v0, v0, 0, v1
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; GCN-NEXT: s_setpc_b64 s[30:31]
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%conv = zext i8 %numlowbits to i32
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%onebit = shl i32 1, %conv
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%mask = add nsw i32 %onebit, -1
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%masked = and i32 %mask, %val
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ret i32 %masked
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}
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define i32 @bzhi32_a4_commutative(i32 %val, i32 %numlowbits) nounwind {
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; GCN-LABEL: bzhi32_a4_commutative:
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; GCN: ; %bb.0:
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; GCN-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
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; GCN-NEXT: v_bfe_u32 v0, v0, 0, v1
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; GCN-NEXT: s_setpc_b64 s[30:31]
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%onebit = shl i32 1, %numlowbits
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%mask = add nsw i32 %onebit, -1
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%masked = and i32 %val, %mask ; swapped order
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ret i32 %masked
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}
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; ---------------------------------------------------------------------------- ;
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; Pattern b. 32-bit
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; ---------------------------------------------------------------------------- ;
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define i32 @bzhi32_b0(i32 %val, i32 %numlowbits) nounwind {
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; GCN-LABEL: bzhi32_b0:
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; GCN: ; %bb.0:
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; GCN-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
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; GCN-NEXT: v_bfe_u32 v0, v0, 0, v1
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; GCN-NEXT: s_setpc_b64 s[30:31]
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%notmask = shl i32 -1, %numlowbits
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%mask = xor i32 %notmask, -1
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%masked = and i32 %mask, %val
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ret i32 %masked
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}
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define i32 @bzhi32_b1_indexzext(i32 %val, i8 zeroext %numlowbits) nounwind {
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; GCN-LABEL: bzhi32_b1_indexzext:
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; GCN: ; %bb.0:
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; GCN-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
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; GCN-NEXT: v_bfe_u32 v0, v0, 0, v1
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; GCN-NEXT: s_setpc_b64 s[30:31]
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%conv = zext i8 %numlowbits to i32
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%notmask = shl i32 -1, %conv
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%mask = xor i32 %notmask, -1
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%masked = and i32 %mask, %val
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ret i32 %masked
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}
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define i32 @bzhi32_b4_commutative(i32 %val, i32 %numlowbits) nounwind {
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; GCN-LABEL: bzhi32_b4_commutative:
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; GCN: ; %bb.0:
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; GCN-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
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; GCN-NEXT: v_bfe_u32 v0, v0, 0, v1
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; GCN-NEXT: s_setpc_b64 s[30:31]
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%notmask = shl i32 -1, %numlowbits
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%mask = xor i32 %notmask, -1
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%masked = and i32 %val, %mask ; swapped order
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ret i32 %masked
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}
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; ---------------------------------------------------------------------------- ;
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; Pattern c. 32-bit
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; ---------------------------------------------------------------------------- ;
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define i32 @bzhi32_c0(i32 %val, i32 %numlowbits) nounwind {
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; GCN-LABEL: bzhi32_c0:
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; GCN: ; %bb.0:
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; GCN-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
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; GCN-NEXT: v_bfe_u32 v0, v0, 0, v1
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; GCN-NEXT: s_setpc_b64 s[30:31]
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%numhighbits = sub i32 32, %numlowbits
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%mask = lshr i32 -1, %numhighbits
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%masked = and i32 %mask, %val
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ret i32 %masked
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}
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define i32 @bzhi32_c1_indexzext(i32 %val, i8 %numlowbits) nounwind {
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; SI-LABEL: bzhi32_c1_indexzext:
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; SI: ; %bb.0:
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; SI-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
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; SI-NEXT: v_sub_i32_e32 v1, vcc, 32, v1
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; SI-NEXT: v_lshr_b32_e32 v1, -1, v1
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; SI-NEXT: v_and_b32_e32 v0, v1, v0
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; SI-NEXT: s_setpc_b64 s[30:31]
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;
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; VI-LABEL: bzhi32_c1_indexzext:
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; VI: ; %bb.0:
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; VI-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
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; VI-NEXT: v_sub_u16_e32 v1, 32, v1
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; VI-NEXT: v_lshrrev_b32_e64 v1, v1, -1
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; VI-NEXT: v_and_b32_e32 v0, v1, v0
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; VI-NEXT: s_setpc_b64 s[30:31]
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%numhighbits = sub i8 32, %numlowbits
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%sh_prom = zext i8 %numhighbits to i32
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%mask = lshr i32 -1, %sh_prom
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%masked = and i32 %mask, %val
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ret i32 %masked
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}
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define i32 @bzhi32_c4_commutative(i32 %val, i32 %numlowbits) nounwind {
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; GCN-LABEL: bzhi32_c4_commutative:
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; GCN: ; %bb.0:
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; GCN-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
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; GCN-NEXT: v_bfe_u32 v0, v0, 0, v1
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; GCN-NEXT: s_setpc_b64 s[30:31]
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%numhighbits = sub i32 32, %numlowbits
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%mask = lshr i32 -1, %numhighbits
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%masked = and i32 %val, %mask ; swapped order
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ret i32 %masked
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}
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; ---------------------------------------------------------------------------- ;
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; Pattern d. 32-bit.
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; ---------------------------------------------------------------------------- ;
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define i32 @bzhi32_d0(i32 %val, i32 %numlowbits) nounwind {
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; SI-LABEL: bzhi32_d0:
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; SI: ; %bb.0:
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; SI-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
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; SI-NEXT: v_sub_i32_e32 v1, vcc, 32, v1
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; SI-NEXT: v_lshlrev_b32_e32 v0, v1, v0
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; SI-NEXT: v_lshrrev_b32_e32 v0, v1, v0
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; SI-NEXT: s_setpc_b64 s[30:31]
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;
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; VI-LABEL: bzhi32_d0:
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; VI: ; %bb.0:
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; VI-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
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; VI-NEXT: v_sub_u32_e32 v1, vcc, 32, v1
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; VI-NEXT: v_lshlrev_b32_e32 v0, v1, v0
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; VI-NEXT: v_lshrrev_b32_e32 v0, v1, v0
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; VI-NEXT: s_setpc_b64 s[30:31]
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%numhighbits = sub i32 32, %numlowbits
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%highbitscleared = shl i32 %val, %numhighbits
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%masked = lshr i32 %highbitscleared, %numhighbits
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ret i32 %masked
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}
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define i32 @bzhi32_d1_indexzext(i32 %val, i8 %numlowbits) nounwind {
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; SI-LABEL: bzhi32_d1_indexzext:
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; SI: ; %bb.0:
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; SI-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
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; SI-NEXT: v_sub_i32_e32 v1, vcc, 32, v1
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; SI-NEXT: v_lshlrev_b32_e32 v0, v1, v0
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; SI-NEXT: v_lshrrev_b32_e32 v0, v1, v0
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; SI-NEXT: s_setpc_b64 s[30:31]
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;
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; VI-LABEL: bzhi32_d1_indexzext:
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; VI: ; %bb.0:
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; VI-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
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; VI-NEXT: v_sub_u16_e32 v1, 32, v1
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; VI-NEXT: v_lshlrev_b32_e32 v0, v1, v0
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; VI-NEXT: v_lshrrev_b32_e32 v0, v1, v0
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; VI-NEXT: s_setpc_b64 s[30:31]
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%numhighbits = sub i8 32, %numlowbits
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%sh_prom = zext i8 %numhighbits to i32
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%highbitscleared = shl i32 %val, %sh_prom
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%masked = lshr i32 %highbitscleared, %sh_prom
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ret i32 %masked
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}
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