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[CodeGen] Pre-commit test case related to ComputeNumSignBits for SHL (l…
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…lvm#97695)

Adding test cases aiming at showing possibility to look through
ZERO_EXTEND/ANY_EXTEND when computing number of sign bits for an
SHL node. If all extended bits are shifted out we can analyze the
operand that is extended.
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@bjope @kbluck
bjope authored and kbluck committed Jul 6, 2024
1 parent f30de65 commit 80f000c
Showing 1 changed file with 191 additions and 0 deletions.
191 changes: 191 additions & 0 deletions llvm/test/CodeGen/X86/computenumsignbits-shl.ll
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; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
; RUN: llc < %s -mtriple=x86_64-linux | FileCheck %s --check-prefix=X64

; Verify that we can look through a ZERO_EXTEND/ANY_EXTEND when doing
; ComputeNumSignBits for SHL.
; We use the (sshlsat x, c) -> (shl x, c) fold as verification.
; That fold should happen if c is less than the number of sign bits in x

define void @computeNumSignBits_shl_zext_1(i8 %x, ptr %p) nounwind {
; X64-LABEL: computeNumSignBits_shl_zext_1:
; X64: # %bb.0:
; X64-NEXT: sarb $5, %dil
; X64-NEXT: movzbl %dil, %eax
; X64-NEXT: movl %eax, %ecx
; X64-NEXT: shll $10, %ecx
; X64-NEXT: xorl %edx, %edx
; X64-NEXT: testw %cx, %cx
; X64-NEXT: sets %dl
; X64-NEXT: addl $32767, %edx # imm = 0x7FFF
; X64-NEXT: movl %eax, %edi
; X64-NEXT: shll $11, %edi
; X64-NEXT: movswl %di, %r8d
; X64-NEXT: shrl %r8d
; X64-NEXT: cmpw %r8w, %cx
; X64-NEXT: cmovnel %edx, %edi
; X64-NEXT: movw %di, (%rsi)
; X64-NEXT: movl %eax, %edi
; X64-NEXT: shll $12, %edi
; X64-NEXT: movswl %di, %r8d
; X64-NEXT: shrl $2, %r8d
; X64-NEXT: cmpw %r8w, %cx
; X64-NEXT: cmovnel %edx, %edi
; X64-NEXT: movw %di, (%rsi)
; X64-NEXT: shll $13, %eax
; X64-NEXT: movswl %ax, %edi
; X64-NEXT: shrl $3, %edi
; X64-NEXT: cmpw %di, %cx
; X64-NEXT: cmovnel %edx, %eax
; X64-NEXT: movw %ax, (%rsi)
; X64-NEXT: retq
%ashr = ashr i8 %x, 5
%zext = zext i8 %ashr to i16
%nsb4 = shl i16 %zext, 10
; Expecting (sshlsat x, c) -> (shl x, c) fold.
%tmp1 = call i16 @llvm.sshl.sat.i16(i16 %nsb4, i16 1)
store volatile i16 %tmp1, ptr %p
; Expecting (sshlsat x, c) -> (shl x, c) fold.
%tmp2 = call i16 @llvm.sshl.sat.i16(i16 %nsb4, i16 2)
store volatile i16 %tmp2, ptr %p
; Expecting (sshlsat x, c) -> (shl x, c) fold.
%tmp3 = call i16 @llvm.sshl.sat.i16(i16 %nsb4, i16 3)
store volatile i16 %tmp3, ptr %p
ret void
}

define void @computeNumSignBits_shl_zext_2(i8 %x, ptr %p) nounwind {
; X64-LABEL: computeNumSignBits_shl_zext_2:
; X64: # %bb.0:
; X64-NEXT: sarb $5, %dil
; X64-NEXT: movzbl %dil, %eax
; X64-NEXT: movl %eax, %ecx
; X64-NEXT: shll $10, %ecx
; X64-NEXT: xorl %edx, %edx
; X64-NEXT: testw %cx, %cx
; X64-NEXT: sets %dl
; X64-NEXT: addl $32767, %edx # imm = 0x7FFF
; X64-NEXT: shll $14, %eax
; X64-NEXT: movswl %ax, %edi
; X64-NEXT: shrl $4, %edi
; X64-NEXT: cmpw %di, %cx
; X64-NEXT: cmovnel %edx, %eax
; X64-NEXT: movw %ax, (%rsi)
; X64-NEXT: retq
%ashr = ashr i8 %x, 5
%zext = zext i8 %ashr to i16
%nsb4 = shl i16 %zext, 10
; 4 sign bits. Not expecting (sshlsat x, c) -> (shl x, c) fold.
%tmp4 = call i16 @llvm.sshl.sat.i16(i16 %nsb4, i16 4)
store volatile i16 %tmp4, ptr %p
ret void
}

define void @computeNumSignBits_shl_zext_vec_1(<2 x i8> %x, ptr %p) nounwind {
; X64-LABEL: computeNumSignBits_shl_zext_vec_1:
; X64: # %bb.0:
; X64-NEXT: psrlw $5, %xmm0
; X64-NEXT: pand {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %xmm0
; X64-NEXT: movdqa {{.*#+}} xmm1 = [4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4]
; X64-NEXT: pxor %xmm1, %xmm0
; X64-NEXT: psubb %xmm1, %xmm0
; X64-NEXT: pxor %xmm1, %xmm1
; X64-NEXT: punpcklbw {{.*#+}} xmm0 = xmm0[0],xmm1[0],xmm0[1],xmm1[1],xmm0[2],xmm1[2],xmm0[3],xmm1[3],xmm0[4],xmm1[4],xmm0[5],xmm1[5],xmm0[6],xmm1[6],xmm0[7],xmm1[7]
; X64-NEXT: pmullw {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %xmm0 # [1024,4096,u,u,u,u,u,u]
; X64-NEXT: movdqa {{.*#+}} xmm2 = [32768,32768,32768,32768,32768,32768,32768,32768]
; X64-NEXT: pand %xmm0, %xmm2
; X64-NEXT: pcmpgtw %xmm0, %xmm1
; X64-NEXT: pandn {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %xmm1
; X64-NEXT: por %xmm2, %xmm1
; X64-NEXT: movdqa %xmm0, %xmm2
; X64-NEXT: paddw %xmm0, %xmm2
; X64-NEXT: movdqa %xmm2, %xmm3
; X64-NEXT: psraw $1, %xmm3
; X64-NEXT: pcmpeqw %xmm0, %xmm3
; X64-NEXT: movdqa %xmm3, %xmm0
; X64-NEXT: pandn %xmm1, %xmm0
; X64-NEXT: pand %xmm2, %xmm3
; X64-NEXT: por %xmm0, %xmm3
; X64-NEXT: movd %xmm3, (%rdi)
; X64-NEXT: retq
%ashr = ashr <2 x i8> %x, <i8 5, i8 5>
%zext = zext <2 x i8> %ashr to <2 x i16>
%nsb4_2 = shl <2 x i16> %zext, <i16 10, i16 12>
; Expecting (sshlsat x, c) -> (shl x, c) fold.
%tmp1 = call <2 x i16> @llvm.sshl.sat.v2i16(<2 x i16> %nsb4_2, <2 x i16> <i16 1, i16 1>)
store volatile <2 x i16> %tmp1, ptr %p
ret void
}

define void @computeNumSignBits_shl_zext_vec_2(<2 x i8> %x, ptr %p) nounwind {
; X64-LABEL: computeNumSignBits_shl_zext_vec_2:
; X64: # %bb.0:
; X64-NEXT: psrlw $5, %xmm0
; X64-NEXT: pand {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %xmm0
; X64-NEXT: movdqa {{.*#+}} xmm1 = [4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4]
; X64-NEXT: pxor %xmm1, %xmm0
; X64-NEXT: psubb %xmm1, %xmm0
; X64-NEXT: pxor %xmm1, %xmm1
; X64-NEXT: punpcklbw {{.*#+}} xmm0 = xmm0[0],xmm1[0],xmm0[1],xmm1[1],xmm0[2],xmm1[2],xmm0[3],xmm1[3],xmm0[4],xmm1[4],xmm0[5],xmm1[5],xmm0[6],xmm1[6],xmm0[7],xmm1[7]
; X64-NEXT: pmullw {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %xmm0 # [1024,4096,u,u,u,u,u,u]
; X64-NEXT: movdqa {{.*#+}} xmm2 = [32768,32768,32768,32768,32768,32768,32768,32768]
; X64-NEXT: pand %xmm0, %xmm2
; X64-NEXT: pcmpgtw %xmm0, %xmm1
; X64-NEXT: pandn {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %xmm1
; X64-NEXT: por %xmm2, %xmm1
; X64-NEXT: movdqa %xmm0, %xmm2
; X64-NEXT: psllw $2, %xmm2
; X64-NEXT: movdqa %xmm2, %xmm3
; X64-NEXT: psraw $2, %xmm3
; X64-NEXT: pcmpeqw %xmm0, %xmm3
; X64-NEXT: movdqa %xmm3, %xmm0
; X64-NEXT: pandn %xmm1, %xmm0
; X64-NEXT: pand %xmm2, %xmm3
; X64-NEXT: por %xmm0, %xmm3
; X64-NEXT: movd %xmm3, (%rdi)
; X64-NEXT: retq
%ashr = ashr <2 x i8> %x, <i8 5, i8 5>
%zext = zext <2 x i8> %ashr to <2 x i16>
%nsb4_2 = shl <2 x i16> %zext, <i16 10, i16 12>
; Not expecting (sshlsat x, c) -> (shl x, c) fold.
; Because only 2 sign bits in element 1.
%tmp1 = call <2 x i16> @llvm.sshl.sat.v2i16(<2 x i16> %nsb4_2, <2 x i16> <i16 2, i16 2>)
store volatile <2 x i16> %tmp1, ptr %p
ret void
}

define void @computeNumSignBits_shl_zext_vec_3(<2 x i8> %x, ptr %p) nounwind {
; X64-LABEL: computeNumSignBits_shl_zext_vec_3:
; X64: # %bb.0:
; X64-NEXT: psrlw $5, %xmm0
; X64-NEXT: pand {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %xmm0
; X64-NEXT: movdqa {{.*#+}} xmm1 = [4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4]
; X64-NEXT: pxor %xmm1, %xmm0
; X64-NEXT: psubb %xmm1, %xmm0
; X64-NEXT: pxor %xmm1, %xmm1
; X64-NEXT: punpcklbw {{.*#+}} xmm0 = xmm0[0],xmm1[0],xmm0[1],xmm1[1],xmm0[2],xmm1[2],xmm0[3],xmm1[3],xmm0[4],xmm1[4],xmm0[5],xmm1[5],xmm0[6],xmm1[6],xmm0[7],xmm1[7]
; X64-NEXT: pmullw {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %xmm0 # [16384,4096,u,u,u,u,u,u]
; X64-NEXT: movdqa {{.*#+}} xmm2 = [32768,32768,32768,32768,32768,32768,32768,32768]
; X64-NEXT: pand %xmm0, %xmm2
; X64-NEXT: pcmpgtw %xmm0, %xmm1
; X64-NEXT: pandn {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %xmm1
; X64-NEXT: por %xmm2, %xmm1
; X64-NEXT: movdqa %xmm0, %xmm2
; X64-NEXT: paddw %xmm0, %xmm2
; X64-NEXT: movdqa %xmm2, %xmm3
; X64-NEXT: psraw $1, %xmm3
; X64-NEXT: pcmpeqw %xmm0, %xmm3
; X64-NEXT: movdqa %xmm3, %xmm0
; X64-NEXT: pandn %xmm1, %xmm0
; X64-NEXT: pand %xmm2, %xmm3
; X64-NEXT: por %xmm0, %xmm3
; X64-NEXT: movd %xmm3, (%rdi)
; X64-NEXT: retq
%ashr = ashr <2 x i8> %x, <i8 5, i8 5>
%zext = zext <2 x i8> %ashr to <2 x i16>
%nsb1_2 = shl <2 x i16> %zext, <i16 14, i16 12>
; Not expecting (sshlsat x, c) -> (shl x, c) fold.
; Because all sign bits shifted out for element 0
%tmp1 = call <2 x i16> @llvm.sshl.sat.v2i16(<2 x i16> %nsb1_2, <2 x i16> <i16 1, i16 1>)
store volatile <2 x i16> %tmp1, ptr %p
ret void
}

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