Files
clang-p2996/llvm/test/CodeGen/X86/pr45995.ll
Matthias Braun 189900eb14 X86: Stop assigning register costs for longer encodings.
This stops reporting CostPerUse 1 for `R8`-`R15` and `XMM8`-`XMM31`.
This was previously done because instruction encoding require a REX
prefix when using them resulting in longer instruction encodings. I
found that this regresses the quality of the register allocation as the
costs impose an ordering on eviction candidates. I also feel that there
is a bit of an impedance mismatch as the actual costs occure when
encoding instructions using those registers, but the order of VReg
assignments is not primarily ordered by number of Defs+Uses.

I did extensive measurements with the llvm-test-suite wiht SPEC2006 +
SPEC2017 included, internal services showed similar patterns. Generally
there are a log of improvements but also a lot of regression. But on
average the allocation quality seems to improve at a small code size
regression.

Results for measuring static and dynamic instruction counts:

Dynamic Counts (scaled by execution frequency) / Optimization Remarks:
    Spills+FoldedSpills   -5.6%
    Reloads+FoldedReloads -4.2%
    Copies                -0.1%

Static / LLVM Statistics:
    regalloc.NumSpills    mean -1.6%, geomean -2.8%
    regalloc.NumReloads   mean -1.7%, geomean -3.1%
    size..text            mean +0.4%, geomean +0.4%

Static / LLVM Statistics:
    mean -2.2%, geomean -3.1%) regalloc.NumSpills
    mean -2.6%, geomean -3.9%) regalloc.NumReloads
    mean +0.6%, geomean +0.6%) size..text

Static / LLVM Statistics:
    regalloc.NumSpills   mean -3.0%
    regalloc.NumReloads  mean -3.3%
    size..text           mean +0.3%, geomean +0.3%

Differential Revision: https://reviews.llvm.org/D133902
2022-09-30 16:01:33 -07:00

148 lines
4.7 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; RUN: llc -O3 --x86-asm-syntax=intel -mtriple=x86_64 -mattr=avx < %s | FileCheck %s
define void @extracter0([4 x <4 x i1>] %matrix) {
; CHECK-LABEL: extracter0:
; CHECK: # %bb.0:
; CHECK-NEXT: push rbp
; CHECK-NEXT: .cfi_def_cfa_offset 16
; CHECK-NEXT: push r14
; CHECK-NEXT: .cfi_def_cfa_offset 24
; CHECK-NEXT: push rbx
; CHECK-NEXT: .cfi_def_cfa_offset 32
; CHECK-NEXT: .cfi_offset rbx, -32
; CHECK-NEXT: .cfi_offset r14, -24
; CHECK-NEXT: .cfi_offset rbp, -16
; CHECK-NEXT: vpslld xmm0, xmm0, 31
; CHECK-NEXT: vmovmskps edi, xmm0
; CHECK-NEXT: mov ebx, edi
; CHECK-NEXT: shr bl, 3
; CHECK-NEXT: mov ebp, edi
; CHECK-NEXT: and bpl, 4
; CHECK-NEXT: shr bpl, 2
; CHECK-NEXT: mov r14d, edi
; CHECK-NEXT: and r14b, 2
; CHECK-NEXT: shr r14b
; CHECK-NEXT: call print_i1@PLT
; CHECK-NEXT: movzx edi, r14b
; CHECK-NEXT: call print_i1@PLT
; CHECK-NEXT: movzx edi, bpl
; CHECK-NEXT: call print_i1@PLT
; CHECK-NEXT: movzx edi, bl
; CHECK-NEXT: call print_i1@PLT
; CHECK-NEXT: pop rbx
; CHECK-NEXT: .cfi_def_cfa_offset 24
; CHECK-NEXT: pop r14
; CHECK-NEXT: .cfi_def_cfa_offset 16
; CHECK-NEXT: pop rbp
; CHECK-NEXT: .cfi_def_cfa_offset 8
; CHECK-NEXT: ret
%1 = extractvalue [4 x <4 x i1>] %matrix, 0
%2 = extractelement <4 x i1> %1, i64 0
%3 = extractelement <4 x i1> %1, i64 1
%4 = extractelement <4 x i1> %1, i64 2
%5 = extractelement <4 x i1> %1, i64 3
call void @print_i1(i1 %2)
call void @print_i1(i1 %3)
call void @print_i1(i1 %4)
call void @print_i1(i1 %5)
ret void
}
define void @extracter1([4 x <4 x i1>] %matrix) {
; CHECK-LABEL: extracter1:
; CHECK: # %bb.0:
; CHECK-NEXT: push rbp
; CHECK-NEXT: .cfi_def_cfa_offset 16
; CHECK-NEXT: push r15
; CHECK-NEXT: .cfi_def_cfa_offset 24
; CHECK-NEXT: push r14
; CHECK-NEXT: .cfi_def_cfa_offset 32
; CHECK-NEXT: push r13
; CHECK-NEXT: .cfi_def_cfa_offset 40
; CHECK-NEXT: push r12
; CHECK-NEXT: .cfi_def_cfa_offset 48
; CHECK-NEXT: push rbx
; CHECK-NEXT: .cfi_def_cfa_offset 56
; CHECK-NEXT: push rax
; CHECK-NEXT: .cfi_def_cfa_offset 64
; CHECK-NEXT: .cfi_offset rbx, -56
; CHECK-NEXT: .cfi_offset r12, -48
; CHECK-NEXT: .cfi_offset r13, -40
; CHECK-NEXT: .cfi_offset r14, -32
; CHECK-NEXT: .cfi_offset r15, -24
; CHECK-NEXT: .cfi_offset rbp, -16
; CHECK-NEXT: vpslld xmm1, xmm1, 31
; CHECK-NEXT: vmovmskps ebx, xmm1
; CHECK-NEXT: mov eax, ebx
; CHECK-NEXT: shr al, 3
; CHECK-NEXT: mov byte ptr [rsp + 7], al # 1-byte Spill
; CHECK-NEXT: mov r14d, ebx
; CHECK-NEXT: and r14b, 4
; CHECK-NEXT: shr r14b, 2
; CHECK-NEXT: mov r15d, ebx
; CHECK-NEXT: and r15b, 2
; CHECK-NEXT: shr r15b
; CHECK-NEXT: vpslld xmm0, xmm0, 31
; CHECK-NEXT: vmovmskps edi, xmm0
; CHECK-NEXT: mov r12d, edi
; CHECK-NEXT: shr r12b, 3
; CHECK-NEXT: mov r13d, edi
; CHECK-NEXT: and r13b, 4
; CHECK-NEXT: shr r13b, 2
; CHECK-NEXT: mov ebp, edi
; CHECK-NEXT: and bpl, 2
; CHECK-NEXT: shr bpl
; CHECK-NEXT: call print_i1@PLT
; CHECK-NEXT: movzx edi, bpl
; CHECK-NEXT: call print_i1@PLT
; CHECK-NEXT: movzx edi, r13b
; CHECK-NEXT: call print_i1@PLT
; CHECK-NEXT: movzx edi, r12b
; CHECK-NEXT: call print_i1@PLT
; CHECK-NEXT: mov edi, ebx
; CHECK-NEXT: call print_i1@PLT
; CHECK-NEXT: movzx edi, r15b
; CHECK-NEXT: call print_i1@PLT
; CHECK-NEXT: movzx edi, r14b
; CHECK-NEXT: call print_i1@PLT
; CHECK-NEXT: movzx edi, byte ptr [rsp + 7] # 1-byte Folded Reload
; CHECK-NEXT: call print_i1@PLT
; CHECK-NEXT: add rsp, 8
; CHECK-NEXT: .cfi_def_cfa_offset 56
; CHECK-NEXT: pop rbx
; CHECK-NEXT: .cfi_def_cfa_offset 48
; CHECK-NEXT: pop r12
; CHECK-NEXT: .cfi_def_cfa_offset 40
; CHECK-NEXT: pop r13
; CHECK-NEXT: .cfi_def_cfa_offset 32
; CHECK-NEXT: pop r14
; CHECK-NEXT: .cfi_def_cfa_offset 24
; CHECK-NEXT: pop r15
; CHECK-NEXT: .cfi_def_cfa_offset 16
; CHECK-NEXT: pop rbp
; CHECK-NEXT: .cfi_def_cfa_offset 8
; CHECK-NEXT: ret
%1 = extractvalue [4 x <4 x i1>] %matrix, 0
%2 = extractelement <4 x i1> %1, i64 0
%3 = extractelement <4 x i1> %1, i64 1
%4 = extractelement <4 x i1> %1, i64 2
%5 = extractelement <4 x i1> %1, i64 3
call void @print_i1(i1 %2)
call void @print_i1(i1 %3)
call void @print_i1(i1 %4)
call void @print_i1(i1 %5)
%6 = extractvalue [4 x <4 x i1>] %matrix, 1
%7 = extractelement <4 x i1> %6, i64 0
%8 = extractelement <4 x i1> %6, i64 1
%9 = extractelement <4 x i1> %6, i64 2
%10 = extractelement <4 x i1> %6, i64 3
call void @print_i1(i1 %7)
call void @print_i1(i1 %8)
call void @print_i1(i1 %9)
call void @print_i1(i1 %10)
ret void
}
declare void @print_i1(i1)