f0dd12ec5c
The first attempt missed changing test files for tools (update_llc_test_checks.py). Original commit message: This implements the main suggested change from issue #56498. Using the shorter (non-extending) instruction with only -Oz ("minsize") rather than -Os ("optsize") is left as a possible follow-up. As noted in the bug report, the zero-extending load may have shorter latency/better throughput across a wide range of x86 micro-arches, and it avoids a potential false dependency. The cost is an extra instruction byte. This could cause perf ups and downs from secondary effects, but I don't think it is possible to account for those in advance, and that will likely also depend on exact micro-arch. This does bring LLVM x86 codegen more in line with existing gcc codegen, so if problems are exposed they are more likely to occur for both compilers. Differential Revision: https://reviews.llvm.org/D129775
104 lines
3.1 KiB
LLVM
104 lines
3.1 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
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; RUN: llc < %s -mtriple=i686-unknown-unknown -mattr=+sse2 | FileCheck %s --check-prefix=CHECK --check-prefix=X86
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; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=+sse2 | FileCheck %s --check-prefix=CHECK --check-prefix=X64
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define i32 @extractelt_undef_insertelt(i32 %x, i32 %y) {
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; CHECK-LABEL: extractelt_undef_insertelt:
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; CHECK: # %bb.0:
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; CHECK-NEXT: ret{{[l|q]}}
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%b = insertelement <4 x i32> zeroinitializer, i32 %x, i64 3
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%c = icmp uge i32 %y, %y
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%d = extractelement <4 x i32> %b, i1 %c
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ret i32 %d
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}
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define i8 @extractelt_bitcast(i32 %x) nounwind {
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; X86-LABEL: extractelt_bitcast:
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; X86: # %bb.0:
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; X86-NEXT: movzbl {{[0-9]+}}(%esp), %eax
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; X86-NEXT: retl
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;
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; X64-LABEL: extractelt_bitcast:
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; X64: # %bb.0:
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; X64-NEXT: movl %edi, %eax
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; X64-NEXT: # kill: def $al killed $al killed $eax
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; X64-NEXT: retq
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%bc = bitcast i32 %x to <4 x i8>
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%ext = extractelement <4 x i8> %bc, i32 0
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ret i8 %ext
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}
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define i8 @extractelt_bitcast_extra_use(i32 %x, ptr %p) nounwind {
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; X86-LABEL: extractelt_bitcast_extra_use:
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; X86: # %bb.0:
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; X86-NEXT: movl {{[0-9]+}}(%esp), %eax
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; X86-NEXT: movl {{[0-9]+}}(%esp), %ecx
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; X86-NEXT: movl %eax, (%ecx)
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; X86-NEXT: # kill: def $al killed $al killed $eax
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; X86-NEXT: retl
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;
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; X64-LABEL: extractelt_bitcast_extra_use:
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; X64: # %bb.0:
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; X64-NEXT: movl %edi, %eax
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; X64-NEXT: movl %edi, (%rsi)
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; X64-NEXT: # kill: def $al killed $al killed $eax
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; X64-NEXT: retq
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%bc = bitcast i32 %x to <4 x i8>
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store <4 x i8> %bc, ptr %p
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%ext = extractelement <4 x i8> %bc, i32 0
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ret i8 %ext
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}
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define i32 @trunc_i64_to_i32_le(i64 %x) {
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; X86-LABEL: trunc_i64_to_i32_le:
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; X86: # %bb.0:
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; X86-NEXT: movl {{[0-9]+}}(%esp), %eax
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; X86-NEXT: retl
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;
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; X64-LABEL: trunc_i64_to_i32_le:
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; X64: # %bb.0:
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; X64-NEXT: movq %rdi, %rax
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; X64-NEXT: # kill: def $eax killed $eax killed $rax
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; X64-NEXT: retq
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%ins = insertelement <2 x i64> undef, i64 %x, i32 0
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%bc = bitcast <2 x i64> %ins to <4 x i32>
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%ext = extractelement <4 x i32> %bc, i32 0
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ret i32 %ext
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}
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define i16 @trunc_i64_to_i16_le(i64 %x) {
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; X86-LABEL: trunc_i64_to_i16_le:
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; X86: # %bb.0:
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; X86-NEXT: movl {{[0-9]+}}(%esp), %eax
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; X86-NEXT: # kill: def $ax killed $ax killed $eax
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; X86-NEXT: retl
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;
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; X64-LABEL: trunc_i64_to_i16_le:
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; X64: # %bb.0:
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; X64-NEXT: movq %rdi, %rax
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; X64-NEXT: # kill: def $ax killed $ax killed $rax
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; X64-NEXT: retq
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%ins = insertelement <2 x i64> undef, i64 %x, i32 0
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%bc = bitcast <2 x i64> %ins to <8 x i16>
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%ext = extractelement <8 x i16> %bc, i32 0
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ret i16 %ext
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}
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define i8 @trunc_i32_to_i8_le(i32 %x) {
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; X86-LABEL: trunc_i32_to_i8_le:
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; X86: # %bb.0:
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; X86-NEXT: movzbl {{[0-9]+}}(%esp), %eax
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; X86-NEXT: retl
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;
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; X64-LABEL: trunc_i32_to_i8_le:
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; X64: # %bb.0:
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; X64-NEXT: movl %edi, %eax
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; X64-NEXT: # kill: def $al killed $al killed $eax
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; X64-NEXT: retq
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%ins = insertelement <4 x i32> undef, i32 %x, i32 0
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%bc = bitcast <4 x i32> %ins to <16 x i8>
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%ext = extractelement <16 x i8> %bc, i32 0
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ret i8 %ext
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}
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