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llvm-mirror/test/CodeGen/X86/vec_set-A.ll
Sanjay Patel 4a6def05d5 [x86] favor vector constant load to avoid GPR to XMM transfer, part 2
This replaces the build_vector lowering code that was just added in
D80013
and matches the pattern later from the x86-specific "vzext_movl".
That seems to result in the same or better improvements and gets rid
of the 'TODO' items from that patch.

AFAICT, we always shrink wider constant vectors to 128-bit on these
patterns, so we still get the implicit zero-extension to ymm/zmm
without wasting space on larger vector constants. There's a trade-off
there because that means we miss potential load-folding.

Similarly, we could load scalar constants here with implicit
zero-extension even to 128-bit. That saves constant space, but it
means we forego load-folding, and so it increases register pressure.
This seems like a good middle-ground between those 2 options.

Differential Revision: https://reviews.llvm.org/D80131
2020-05-25 08:01:48 -04:00

18 lines
546 B
LLVM

; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; RUN: llc < %s -mtriple=i386-unknown -mattr=+sse2 | FileCheck %s --check-prefix=X86
; RUN: llc < %s -mtriple=x86_64-unknown -mattr=+sse2 | FileCheck %s --check-prefix=X64
define <2 x i64> @test1() nounwind {
; X86-LABEL: test1:
; X86: # %bb.0:
; X86-NEXT: movaps {{.*#+}} xmm0 = [1,0,0,0]
; X86-NEXT: retl
;
; X64-LABEL: test1:
; X64: # %bb.0:
; X64-NEXT: movaps {{.*#+}} xmm0 = [1,0,0,0]
; X64-NEXT: retq
ret <2 x i64> < i64 1, i64 0 >
}