llvm-project/llvm/test/CodeGen/X86/sse1.ll

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; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; Tests for SSE1 and below, without SSE2+.
; RUN: llc < %s -mtriple=i386-unknown-unknown -mcpu=pentium3 -O3 | FileCheck %s --check-prefix=X32
; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=-sse2,+sse -O3 | FileCheck %s --check-prefix=X64
; PR7993
;define <4 x i32> @test3(<4 x i16> %a) nounwind {
; %c = sext <4 x i16> %a to <4 x i32> ; <<4 x i32>> [#uses=1]
; ret <4 x i32> %c
;}
; This should not emit shuffles to populate the top 2 elements of the 4-element
; vector that this ends up returning.
; rdar://8368414
define <2 x float> @test4(<2 x float> %A, <2 x float> %B) nounwind {
; X32-LABEL: test4:
; X32: # %bb.0: # %entry
; X32-NEXT: movaps %xmm0, %xmm2
; X32-NEXT: shufps {{.*#+}} xmm2 = xmm2[1,1,2,3]
; X32-NEXT: addss %xmm1, %xmm0
; X32-NEXT: shufps {{.*#+}} xmm1 = xmm1[1,1,2,3]
; X32-NEXT: subss %xmm1, %xmm2
; X32-NEXT: unpcklps {{.*#+}} xmm0 = xmm0[0],xmm2[0],xmm0[1],xmm2[1]
; X32-NEXT: retl
;
; X64-LABEL: test4:
; X64: # %bb.0: # %entry
; X64-NEXT: movaps %xmm0, %xmm2
; X64-NEXT: shufps {{.*#+}} xmm2 = xmm2[1,1,2,3]
; X64-NEXT: addss %xmm1, %xmm0
; X64-NEXT: shufps {{.*#+}} xmm1 = xmm1[1,1,2,3]
; X64-NEXT: subss %xmm1, %xmm2
; X64-NEXT: unpcklps {{.*#+}} xmm0 = xmm0[0],xmm2[0],xmm0[1],xmm2[1]
; X64-NEXT: retq
entry:
%tmp7 = extractelement <2 x float> %A, i32 0
%tmp5 = extractelement <2 x float> %A, i32 1
%tmp3 = extractelement <2 x float> %B, i32 0
%tmp1 = extractelement <2 x float> %B, i32 1
%add.r = fadd float %tmp7, %tmp3
%add.i = fsub float %tmp5, %tmp1
%tmp11 = insertelement <2 x float> undef, float %add.r, i32 0
%tmp9 = insertelement <2 x float> %tmp11, float %add.i, i32 1
ret <2 x float> %tmp9
}
; We used to get stuck in type legalization for this example when lowering the
; vselect. With SSE1 v4f32 is a legal type but v4i1 (or any vector integer type)
; is not. We used to ping pong between splitting the vselect for the v4i
; condition operand and widening the resulting vselect for the v4f32 result.
; PR18036
define <4 x float> @vselect(<4 x float>*%p, <4 x i32> %q) {
; X32-LABEL: vselect:
; X32: # %bb.0: # %entry
; X32-NEXT: cmpl $0, {{[0-9]+}}(%esp)
; X32-NEXT: xorps %xmm0, %xmm0
; X32-NEXT: je .LBB1_1
; X32-NEXT: # %bb.2: # %entry
; X32-NEXT: xorps %xmm1, %xmm1
; X32-NEXT: cmpl $0, {{[0-9]+}}(%esp)
; X32-NEXT: jne .LBB1_5
Codegen: Make chains from trellis-shaped CFGs Lay out trellis-shaped CFGs optimally. A trellis of the shape below: A B |\ /| | \ / | | X | | / \ | |/ \| C D would be laid out A; B->C ; D by the current layout algorithm. Now we identify trellises and lay them out either A->C; B->D or A->D; B->C. This scales with an increasing number of predecessors. A trellis is a a group of 2 or more predecessor blocks that all have the same successors. because of this we can tail duplicate to extend existing trellises. As an example consider the following CFG: B D F H / \ / \ / \ / \ A---C---E---G---Ret Where A,C,E,G are all small (Currently 2 instructions). The CFG preserving layout is then A,B,C,D,E,F,G,H,Ret. The current code will copy C into B, E into D and G into F and yield the layout A,C,B(C),E,D(E),F(G),G,H,ret define void @straight_test(i32 %tag) { entry: br label %test1 test1: ; A %tagbit1 = and i32 %tag, 1 %tagbit1eq0 = icmp eq i32 %tagbit1, 0 br i1 %tagbit1eq0, label %test2, label %optional1 optional1: ; B call void @a() br label %test2 test2: ; C %tagbit2 = and i32 %tag, 2 %tagbit2eq0 = icmp eq i32 %tagbit2, 0 br i1 %tagbit2eq0, label %test3, label %optional2 optional2: ; D call void @b() br label %test3 test3: ; E %tagbit3 = and i32 %tag, 4 %tagbit3eq0 = icmp eq i32 %tagbit3, 0 br i1 %tagbit3eq0, label %test4, label %optional3 optional3: ; F call void @c() br label %test4 test4: ; G %tagbit4 = and i32 %tag, 8 %tagbit4eq0 = icmp eq i32 %tagbit4, 0 br i1 %tagbit4eq0, label %exit, label %optional4 optional4: ; H call void @d() br label %exit exit: ret void } here is the layout after D27742: straight_test: # @straight_test ; ... Prologue elided ; BB#0: # %entry ; A (merged with test1) ; ... More prologue elided mr 30, 3 andi. 3, 30, 1 bc 12, 1, .LBB0_2 ; BB#1: # %test2 ; C rlwinm. 3, 30, 0, 30, 30 beq 0, .LBB0_3 b .LBB0_4 .LBB0_2: # %optional1 ; B (copy of C) bl a nop rlwinm. 3, 30, 0, 30, 30 bne 0, .LBB0_4 .LBB0_3: # %test3 ; E rlwinm. 3, 30, 0, 29, 29 beq 0, .LBB0_5 b .LBB0_6 .LBB0_4: # %optional2 ; D (copy of E) bl b nop rlwinm. 3, 30, 0, 29, 29 bne 0, .LBB0_6 .LBB0_5: # %test4 ; G rlwinm. 3, 30, 0, 28, 28 beq 0, .LBB0_8 b .LBB0_7 .LBB0_6: # %optional3 ; F (copy of G) bl c nop rlwinm. 3, 30, 0, 28, 28 beq 0, .LBB0_8 .LBB0_7: # %optional4 ; H bl d nop .LBB0_8: # %exit ; Ret ld 30, 96(1) # 8-byte Folded Reload addi 1, 1, 112 ld 0, 16(1) mtlr 0 blr The tail-duplication has produced some benefit, but it has also produced a trellis which is not laid out optimally. With this patch, we improve the layouts of such trellises, and decrease the cost calculation for tail-duplication accordingly. This patch produces the layout A,C,E,G,B,D,F,H,Ret. This layout does have back edges, which is a negative, but it has a bigger compensating positive, which is that it handles the case where there are long strings of skipped blocks much better than the original layout. Both layouts handle runs of executed blocks equally well. Branch prediction also improves if there is any correlation between subsequent optional blocks. Here is the resulting concrete layout: straight_test: # @straight_test ; BB#0: # %entry ; A (merged with test1) mr 30, 3 andi. 3, 30, 1 bc 12, 1, .LBB0_4 ; BB#1: # %test2 ; C rlwinm. 3, 30, 0, 30, 30 bne 0, .LBB0_5 .LBB0_2: # %test3 ; E rlwinm. 3, 30, 0, 29, 29 bne 0, .LBB0_6 .LBB0_3: # %test4 ; G rlwinm. 3, 30, 0, 28, 28 bne 0, .LBB0_7 b .LBB0_8 .LBB0_4: # %optional1 ; B (Copy of C) bl a nop rlwinm. 3, 30, 0, 30, 30 beq 0, .LBB0_2 .LBB0_5: # %optional2 ; D (Copy of E) bl b nop rlwinm. 3, 30, 0, 29, 29 beq 0, .LBB0_3 .LBB0_6: # %optional3 ; F (Copy of G) bl c nop rlwinm. 3, 30, 0, 28, 28 beq 0, .LBB0_8 .LBB0_7: # %optional4 ; H bl d nop .LBB0_8: # %exit Differential Revision: https://reviews.llvm.org/D28522 llvm-svn: 295223
2017-02-16 03:49:14 +08:00
; X32-NEXT: .LBB1_4:
; X32-NEXT: movss {{.*#+}} xmm2 = mem[0],zero,zero,zero
; X32-NEXT: cmpl $0, {{[0-9]+}}(%esp)
; X32-NEXT: jne .LBB1_8
; X32-NEXT: .LBB1_7:
; X32-NEXT: movss {{.*#+}} xmm3 = mem[0],zero,zero,zero
; X32-NEXT: cmpl $0, {{[0-9]+}}(%esp)
; X32-NEXT: unpcklps {{.*#+}} xmm2 = xmm2[0],xmm3[0],xmm2[1],xmm3[1]
; X32-NEXT: je .LBB1_10
; X32-NEXT: jmp .LBB1_11
; X32-NEXT: .LBB1_1:
; X32-NEXT: movss {{.*#+}} xmm1 = mem[0],zero,zero,zero
; X32-NEXT: cmpl $0, {{[0-9]+}}(%esp)
; X32-NEXT: je .LBB1_4
; X32-NEXT: .LBB1_5: # %entry
; X32-NEXT: xorps %xmm2, %xmm2
; X32-NEXT: cmpl $0, {{[0-9]+}}(%esp)
; X32-NEXT: je .LBB1_7
; X32-NEXT: .LBB1_8: # %entry
; X32-NEXT: xorps %xmm3, %xmm3
; X32-NEXT: cmpl $0, {{[0-9]+}}(%esp)
; X32-NEXT: unpcklps {{.*#+}} xmm2 = xmm2[0],xmm3[0],xmm2[1],xmm3[1]
; X32-NEXT: jne .LBB1_11
; X32-NEXT: .LBB1_10:
; X32-NEXT: movss {{.*#+}} xmm0 = mem[0],zero,zero,zero
; X32-NEXT: .LBB1_11: # %entry
; X32-NEXT: unpcklps {{.*#+}} xmm0 = xmm0[0],xmm1[0],xmm0[1],xmm1[1]
; X32-NEXT: movlhps {{.*#+}} xmm0 = xmm0[0],xmm2[0]
; X32-NEXT: retl
;
; X64-LABEL: vselect:
; X64: # %bb.0: # %entry
; X64-NEXT: testl %edx, %edx
; X64-NEXT: xorps %xmm0, %xmm0
; X64-NEXT: je .LBB1_1
; X64-NEXT: # %bb.2: # %entry
; X64-NEXT: xorps %xmm1, %xmm1
; X64-NEXT: testl %ecx, %ecx
; X64-NEXT: jne .LBB1_5
Codegen: Make chains from trellis-shaped CFGs Lay out trellis-shaped CFGs optimally. A trellis of the shape below: A B |\ /| | \ / | | X | | / \ | |/ \| C D would be laid out A; B->C ; D by the current layout algorithm. Now we identify trellises and lay them out either A->C; B->D or A->D; B->C. This scales with an increasing number of predecessors. A trellis is a a group of 2 or more predecessor blocks that all have the same successors. because of this we can tail duplicate to extend existing trellises. As an example consider the following CFG: B D F H / \ / \ / \ / \ A---C---E---G---Ret Where A,C,E,G are all small (Currently 2 instructions). The CFG preserving layout is then A,B,C,D,E,F,G,H,Ret. The current code will copy C into B, E into D and G into F and yield the layout A,C,B(C),E,D(E),F(G),G,H,ret define void @straight_test(i32 %tag) { entry: br label %test1 test1: ; A %tagbit1 = and i32 %tag, 1 %tagbit1eq0 = icmp eq i32 %tagbit1, 0 br i1 %tagbit1eq0, label %test2, label %optional1 optional1: ; B call void @a() br label %test2 test2: ; C %tagbit2 = and i32 %tag, 2 %tagbit2eq0 = icmp eq i32 %tagbit2, 0 br i1 %tagbit2eq0, label %test3, label %optional2 optional2: ; D call void @b() br label %test3 test3: ; E %tagbit3 = and i32 %tag, 4 %tagbit3eq0 = icmp eq i32 %tagbit3, 0 br i1 %tagbit3eq0, label %test4, label %optional3 optional3: ; F call void @c() br label %test4 test4: ; G %tagbit4 = and i32 %tag, 8 %tagbit4eq0 = icmp eq i32 %tagbit4, 0 br i1 %tagbit4eq0, label %exit, label %optional4 optional4: ; H call void @d() br label %exit exit: ret void } here is the layout after D27742: straight_test: # @straight_test ; ... Prologue elided ; BB#0: # %entry ; A (merged with test1) ; ... More prologue elided mr 30, 3 andi. 3, 30, 1 bc 12, 1, .LBB0_2 ; BB#1: # %test2 ; C rlwinm. 3, 30, 0, 30, 30 beq 0, .LBB0_3 b .LBB0_4 .LBB0_2: # %optional1 ; B (copy of C) bl a nop rlwinm. 3, 30, 0, 30, 30 bne 0, .LBB0_4 .LBB0_3: # %test3 ; E rlwinm. 3, 30, 0, 29, 29 beq 0, .LBB0_5 b .LBB0_6 .LBB0_4: # %optional2 ; D (copy of E) bl b nop rlwinm. 3, 30, 0, 29, 29 bne 0, .LBB0_6 .LBB0_5: # %test4 ; G rlwinm. 3, 30, 0, 28, 28 beq 0, .LBB0_8 b .LBB0_7 .LBB0_6: # %optional3 ; F (copy of G) bl c nop rlwinm. 3, 30, 0, 28, 28 beq 0, .LBB0_8 .LBB0_7: # %optional4 ; H bl d nop .LBB0_8: # %exit ; Ret ld 30, 96(1) # 8-byte Folded Reload addi 1, 1, 112 ld 0, 16(1) mtlr 0 blr The tail-duplication has produced some benefit, but it has also produced a trellis which is not laid out optimally. With this patch, we improve the layouts of such trellises, and decrease the cost calculation for tail-duplication accordingly. This patch produces the layout A,C,E,G,B,D,F,H,Ret. This layout does have back edges, which is a negative, but it has a bigger compensating positive, which is that it handles the case where there are long strings of skipped blocks much better than the original layout. Both layouts handle runs of executed blocks equally well. Branch prediction also improves if there is any correlation between subsequent optional blocks. Here is the resulting concrete layout: straight_test: # @straight_test ; BB#0: # %entry ; A (merged with test1) mr 30, 3 andi. 3, 30, 1 bc 12, 1, .LBB0_4 ; BB#1: # %test2 ; C rlwinm. 3, 30, 0, 30, 30 bne 0, .LBB0_5 .LBB0_2: # %test3 ; E rlwinm. 3, 30, 0, 29, 29 bne 0, .LBB0_6 .LBB0_3: # %test4 ; G rlwinm. 3, 30, 0, 28, 28 bne 0, .LBB0_7 b .LBB0_8 .LBB0_4: # %optional1 ; B (Copy of C) bl a nop rlwinm. 3, 30, 0, 30, 30 beq 0, .LBB0_2 .LBB0_5: # %optional2 ; D (Copy of E) bl b nop rlwinm. 3, 30, 0, 29, 29 beq 0, .LBB0_3 .LBB0_6: # %optional3 ; F (Copy of G) bl c nop rlwinm. 3, 30, 0, 28, 28 beq 0, .LBB0_8 .LBB0_7: # %optional4 ; H bl d nop .LBB0_8: # %exit Differential Revision: https://reviews.llvm.org/D28522 llvm-svn: 295223
2017-02-16 03:49:14 +08:00
; X64-NEXT: .LBB1_4:
; X64-NEXT: movss {{.*#+}} xmm2 = mem[0],zero,zero,zero
; X64-NEXT: testl %r8d, %r8d
; X64-NEXT: jne .LBB1_8
; X64-NEXT: .LBB1_7:
; X64-NEXT: movss {{.*#+}} xmm3 = mem[0],zero,zero,zero
; X64-NEXT: testl %esi, %esi
; X64-NEXT: unpcklps {{.*#+}} xmm2 = xmm2[0],xmm3[0],xmm2[1],xmm3[1]
; X64-NEXT: je .LBB1_10
; X64-NEXT: jmp .LBB1_11
; X64-NEXT: .LBB1_1:
; X64-NEXT: movss {{.*#+}} xmm1 = mem[0],zero,zero,zero
; X64-NEXT: testl %ecx, %ecx
; X64-NEXT: je .LBB1_4
; X64-NEXT: .LBB1_5: # %entry
; X64-NEXT: xorps %xmm2, %xmm2
; X64-NEXT: testl %r8d, %r8d
; X64-NEXT: je .LBB1_7
; X64-NEXT: .LBB1_8: # %entry
; X64-NEXT: xorps %xmm3, %xmm3
; X64-NEXT: testl %esi, %esi
; X64-NEXT: unpcklps {{.*#+}} xmm2 = xmm2[0],xmm3[0],xmm2[1],xmm3[1]
; X64-NEXT: jne .LBB1_11
; X64-NEXT: .LBB1_10:
; X64-NEXT: movss {{.*#+}} xmm0 = mem[0],zero,zero,zero
; X64-NEXT: .LBB1_11: # %entry
; X64-NEXT: unpcklps {{.*#+}} xmm0 = xmm0[0],xmm1[0],xmm0[1],xmm1[1]
; X64-NEXT: movlhps {{.*#+}} xmm0 = xmm0[0],xmm2[0]
; X64-NEXT: retq
entry:
%a1 = icmp eq <4 x i32> %q, zeroinitializer
%a14 = select <4 x i1> %a1, <4 x float> <float 1.000000e+00, float 2.000000e+00, float 3.000000e+00, float 4.000000e+0> , <4 x float> zeroinitializer
ret <4 x float> %a14
}
; v4i32 isn't legal for SSE1, but this should be cmpps.
define <4 x float> @PR28044(<4 x float> %a0, <4 x float> %a1) nounwind {
; X32-LABEL: PR28044:
; X32: # %bb.0:
; X32-NEXT: cmpeqps %xmm1, %xmm0
; X32-NEXT: retl
;
; X64-LABEL: PR28044:
; X64: # %bb.0:
; X64-NEXT: cmpeqps %xmm1, %xmm0
; X64-NEXT: retq
%cmp = fcmp oeq <4 x float> %a0, %a1
%sext = sext <4 x i1> %cmp to <4 x i32>
%res = bitcast <4 x i32> %sext to <4 x float>
ret <4 x float> %res
}
; Don't crash trying to do the impossible: an integer vector comparison doesn't exist, so we must scalarize.
; https://llvm.org/bugs/show_bug.cgi?id=30512
define <4 x i32> @PR30512(<4 x i32> %x, <4 x i32> %y) nounwind {
; X32-LABEL: PR30512:
; X32: # %bb.0:
; X32-NEXT: pushl %ebx
; X32-NEXT: pushl %edi
; X32-NEXT: pushl %esi
; X32-NEXT: subl $16, %esp
; X32-NEXT: movl {{[0-9]+}}(%esp), %eax
; X32-NEXT: movl {{[0-9]+}}(%esp), %ecx
; X32-NEXT: movl {{[0-9]+}}(%esp), %edx
; X32-NEXT: movl {{[0-9]+}}(%esp), %esi
; X32-NEXT: movl {{[0-9]+}}(%esp), %edi
; X32-NEXT: xorl %ebx, %ebx
; X32-NEXT: cmpl {{[0-9]+}}(%esp), %edi
; X32-NEXT: sete %bl
; X32-NEXT: negl %ebx
; X32-NEXT: movl %ebx, {{[0-9]+}}(%esp)
; X32-NEXT: xorl %ebx, %ebx
; X32-NEXT: cmpl {{[0-9]+}}(%esp), %esi
; X32-NEXT: sete %bl
; X32-NEXT: negl %ebx
; X32-NEXT: movl %ebx, {{[0-9]+}}(%esp)
; X32-NEXT: xorl %ebx, %ebx
; X32-NEXT: cmpl {{[0-9]+}}(%esp), %edx
; X32-NEXT: sete %bl
; X32-NEXT: negl %ebx
; X32-NEXT: movl %ebx, {{[0-9]+}}(%esp)
; X32-NEXT: xorl %edx, %edx
; X32-NEXT: cmpl {{[0-9]+}}(%esp), %ecx
; X32-NEXT: sete %dl
; X32-NEXT: negl %edx
; X32-NEXT: movl %edx, (%esp)
; X32-NEXT: movss {{.*#+}} xmm0 = mem[0],zero,zero,zero
; X32-NEXT: movss {{.*#+}} xmm1 = mem[0],zero,zero,zero
; X32-NEXT: unpcklps {{.*#+}} xmm1 = xmm1[0],xmm0[0],xmm1[1],xmm0[1]
; X32-NEXT: movss {{.*#+}} xmm0 = mem[0],zero,zero,zero
; X32-NEXT: movss {{.*#+}} xmm2 = mem[0],zero,zero,zero
; X32-NEXT: unpcklps {{.*#+}} xmm2 = xmm2[0],xmm0[0],xmm2[1],xmm0[1]
; X32-NEXT: movlhps {{.*#+}} xmm2 = xmm2[0],xmm1[0]
; X32-NEXT: andps {{\.LCPI.*}}, %xmm2
; X32-NEXT: movaps %xmm2, (%eax)
; X32-NEXT: addl $16, %esp
; X32-NEXT: popl %esi
; X32-NEXT: popl %edi
; X32-NEXT: popl %ebx
; X32-NEXT: retl $4
;
; X64-LABEL: PR30512:
; X64: # %bb.0:
; X64-NEXT: xorl %eax, %eax
; X64-NEXT: cmpl {{[0-9]+}}(%rsp), %r8d
; X64-NEXT: sete %al
; X64-NEXT: negl %eax
; X64-NEXT: movl %eax, -{{[0-9]+}}(%rsp)
; X64-NEXT: xorl %eax, %eax
; X64-NEXT: cmpl {{[0-9]+}}(%rsp), %ecx
; X64-NEXT: sete %al
; X64-NEXT: negl %eax
; X64-NEXT: movl %eax, -{{[0-9]+}}(%rsp)
; X64-NEXT: xorl %eax, %eax
; X64-NEXT: cmpl {{[0-9]+}}(%rsp), %edx
; X64-NEXT: sete %al
; X64-NEXT: negl %eax
; X64-NEXT: movl %eax, -{{[0-9]+}}(%rsp)
; X64-NEXT: xorl %eax, %eax
; X64-NEXT: cmpl %r9d, %esi
; X64-NEXT: sete %al
; X64-NEXT: negl %eax
; X64-NEXT: movl %eax, -{{[0-9]+}}(%rsp)
; X64-NEXT: movss {{.*#+}} xmm0 = mem[0],zero,zero,zero
; X64-NEXT: movss {{.*#+}} xmm1 = mem[0],zero,zero,zero
; X64-NEXT: unpcklps {{.*#+}} xmm1 = xmm1[0],xmm0[0],xmm1[1],xmm0[1]
; X64-NEXT: movss {{.*#+}} xmm0 = mem[0],zero,zero,zero
; X64-NEXT: movss {{.*#+}} xmm2 = mem[0],zero,zero,zero
; X64-NEXT: unpcklps {{.*#+}} xmm2 = xmm2[0],xmm0[0],xmm2[1],xmm0[1]
; X64-NEXT: movlhps {{.*#+}} xmm2 = xmm2[0],xmm1[0]
; X64-NEXT: andps {{.*}}(%rip), %xmm2
; X64-NEXT: movaps %xmm2, (%rdi)
; X64-NEXT: movq %rdi, %rax
; X64-NEXT: retq
%cmp = icmp eq <4 x i32> %x, %y
%zext = zext <4 x i1> %cmp to <4 x i32>
ret <4 x i32> %zext
}
Codegen: Make chains from trellis-shaped CFGs Lay out trellis-shaped CFGs optimally. A trellis of the shape below: A B |\ /| | \ / | | X | | / \ | |/ \| C D would be laid out A; B->C ; D by the current layout algorithm. Now we identify trellises and lay them out either A->C; B->D or A->D; B->C. This scales with an increasing number of predecessors. A trellis is a a group of 2 or more predecessor blocks that all have the same successors. because of this we can tail duplicate to extend existing trellises. As an example consider the following CFG: B D F H / \ / \ / \ / \ A---C---E---G---Ret Where A,C,E,G are all small (Currently 2 instructions). The CFG preserving layout is then A,B,C,D,E,F,G,H,Ret. The current code will copy C into B, E into D and G into F and yield the layout A,C,B(C),E,D(E),F(G),G,H,ret define void @straight_test(i32 %tag) { entry: br label %test1 test1: ; A %tagbit1 = and i32 %tag, 1 %tagbit1eq0 = icmp eq i32 %tagbit1, 0 br i1 %tagbit1eq0, label %test2, label %optional1 optional1: ; B call void @a() br label %test2 test2: ; C %tagbit2 = and i32 %tag, 2 %tagbit2eq0 = icmp eq i32 %tagbit2, 0 br i1 %tagbit2eq0, label %test3, label %optional2 optional2: ; D call void @b() br label %test3 test3: ; E %tagbit3 = and i32 %tag, 4 %tagbit3eq0 = icmp eq i32 %tagbit3, 0 br i1 %tagbit3eq0, label %test4, label %optional3 optional3: ; F call void @c() br label %test4 test4: ; G %tagbit4 = and i32 %tag, 8 %tagbit4eq0 = icmp eq i32 %tagbit4, 0 br i1 %tagbit4eq0, label %exit, label %optional4 optional4: ; H call void @d() br label %exit exit: ret void } here is the layout after D27742: straight_test: # @straight_test ; ... Prologue elided ; BB#0: # %entry ; A (merged with test1) ; ... More prologue elided mr 30, 3 andi. 3, 30, 1 bc 12, 1, .LBB0_2 ; BB#1: # %test2 ; C rlwinm. 3, 30, 0, 30, 30 beq 0, .LBB0_3 b .LBB0_4 .LBB0_2: # %optional1 ; B (copy of C) bl a nop rlwinm. 3, 30, 0, 30, 30 bne 0, .LBB0_4 .LBB0_3: # %test3 ; E rlwinm. 3, 30, 0, 29, 29 beq 0, .LBB0_5 b .LBB0_6 .LBB0_4: # %optional2 ; D (copy of E) bl b nop rlwinm. 3, 30, 0, 29, 29 bne 0, .LBB0_6 .LBB0_5: # %test4 ; G rlwinm. 3, 30, 0, 28, 28 beq 0, .LBB0_8 b .LBB0_7 .LBB0_6: # %optional3 ; F (copy of G) bl c nop rlwinm. 3, 30, 0, 28, 28 beq 0, .LBB0_8 .LBB0_7: # %optional4 ; H bl d nop .LBB0_8: # %exit ; Ret ld 30, 96(1) # 8-byte Folded Reload addi 1, 1, 112 ld 0, 16(1) mtlr 0 blr The tail-duplication has produced some benefit, but it has also produced a trellis which is not laid out optimally. With this patch, we improve the layouts of such trellises, and decrease the cost calculation for tail-duplication accordingly. This patch produces the layout A,C,E,G,B,D,F,H,Ret. This layout does have back edges, which is a negative, but it has a bigger compensating positive, which is that it handles the case where there are long strings of skipped blocks much better than the original layout. Both layouts handle runs of executed blocks equally well. Branch prediction also improves if there is any correlation between subsequent optional blocks. Here is the resulting concrete layout: straight_test: # @straight_test ; BB#0: # %entry ; A (merged with test1) mr 30, 3 andi. 3, 30, 1 bc 12, 1, .LBB0_4 ; BB#1: # %test2 ; C rlwinm. 3, 30, 0, 30, 30 bne 0, .LBB0_5 .LBB0_2: # %test3 ; E rlwinm. 3, 30, 0, 29, 29 bne 0, .LBB0_6 .LBB0_3: # %test4 ; G rlwinm. 3, 30, 0, 28, 28 bne 0, .LBB0_7 b .LBB0_8 .LBB0_4: # %optional1 ; B (Copy of C) bl a nop rlwinm. 3, 30, 0, 30, 30 beq 0, .LBB0_2 .LBB0_5: # %optional2 ; D (Copy of E) bl b nop rlwinm. 3, 30, 0, 29, 29 beq 0, .LBB0_3 .LBB0_6: # %optional3 ; F (Copy of G) bl c nop rlwinm. 3, 30, 0, 28, 28 beq 0, .LBB0_8 .LBB0_7: # %optional4 ; H bl d nop .LBB0_8: # %exit Differential Revision: https://reviews.llvm.org/D28522 llvm-svn: 295223
2017-02-16 03:49:14 +08:00
; Fragile test warning - we need to induce the generation of a vselect
; post-legalization to cause the crash seen in:
; https://llvm.org/bugs/show_bug.cgi?id=31672
; Is there a way to do that without an unsafe/fast sqrt intrinsic call?
;
; We now no longer try to lower sqrt using rsqrt with SSE1 only as the
; v4i32 vselect mentioned above should never have been created. We ended up
; scalarizing it anyway.
define <2 x float> @PR31672() #0 {
; X32-LABEL: PR31672:
; X32: # %bb.0:
; X32-NEXT: sqrtps {{\.LCPI.*}}, %xmm0
; X32-NEXT: retl
;
; X64-LABEL: PR31672:
; X64: # %bb.0:
; X64-NEXT: sqrtps {{.*}}(%rip), %xmm0
; X64-NEXT: retq
%t0 = call fast <2 x float> @llvm.sqrt.v2f32(<2 x float> <float 42.0, float 3.0>)
ret <2 x float> %t0
}
declare <2 x float> @llvm.sqrt.v2f32(<2 x float>) #1
attributes #0 = { nounwind "unsafe-fp-math"="true" }