llvm-project/llvm/test/Transforms/InstCombine/fsub.ll

149 lines
4.3 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -instcombine -S | FileCheck %s
; PR4374
define float @test1(float %x, float %y) {
; CHECK-LABEL: @test1(
; CHECK-NEXT: [[T1:%.*]] = fsub float [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: [[T2:%.*]] = fsub float -0.000000e+00, [[T1]]
; CHECK-NEXT: ret float [[T2]]
;
%t1 = fsub float %x, %y
%t2 = fsub float -0.0, %t1
ret float %t2
}
; Can't do anything with the test above because -0.0 - 0.0 = -0.0, but if we have nsz:
; -(X - Y) --> Y - X
define float @neg_sub_nsz(float %x, float %y) {
; CHECK-LABEL: @neg_sub_nsz(
; CHECK-NEXT: [[TMP1:%.*]] = fsub nsz float [[Y:%.*]], [[X:%.*]]
; CHECK-NEXT: ret float [[TMP1]]
;
%t1 = fsub float %x, %y
%t2 = fsub nsz float -0.0, %t1
ret float %t2
}
; If the subtract has another use, we don't do the transform (even though it
; doesn't increase the IR instruction count) because we assume that fneg is
; easier to analyze and generally cheaper than generic fsub.
declare void @use(float)
define float @neg_sub_nsz_extra_use(float %x, float %y) {
; CHECK-LABEL: @neg_sub_nsz_extra_use(
; CHECK-NEXT: [[T1:%.*]] = fsub float [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: [[T2:%.*]] = fsub nsz float -0.000000e+00, [[T1]]
; CHECK-NEXT: call void @use(float [[T1]])
; CHECK-NEXT: ret float [[T2]]
;
%t1 = fsub float %x, %y
%t2 = fsub nsz float -0.0, %t1
call void @use(float %t1)
ret float %t2
}
; With nsz: Z - (X - Y) --> Z + (Y - X)
define float @sub_sub_nsz(float %x, float %y, float %z) {
; CHECK-LABEL: @sub_sub_nsz(
; CHECK-NEXT: [[TMP1:%.*]] = fsub nsz float [[Y:%.*]], [[X:%.*]]
; CHECK-NEXT: [[T2:%.*]] = fadd nsz float [[TMP1]], [[Z:%.*]]
; CHECK-NEXT: ret float [[T2]]
;
%t1 = fsub float %x, %y
%t2 = fsub nsz float %z, %t1
ret float %t2
}
; Same as above: if 'Z' is not -0.0, swap fsub operands and convert to fadd.
define float @sub_sub_known_not_negzero(float %x, float %y) {
; CHECK-LABEL: @sub_sub_known_not_negzero(
; CHECK-NEXT: [[TMP1:%.*]] = fsub float [[Y:%.*]], [[X:%.*]]
; CHECK-NEXT: [[T2:%.*]] = fadd float [[TMP1]], 4.200000e+01
; CHECK-NEXT: ret float [[T2]]
;
%t1 = fsub float %x, %y
%t2 = fsub float 42.0, %t1
ret float %t2
}
; <rdar://problem/7530098>
define double @test2(double %x, double %y) {
; CHECK-LABEL: @test2(
; CHECK-NEXT: [[T1:%.*]] = fadd double [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: [[T2:%.*]] = fsub double [[X]], [[T1]]
; CHECK-NEXT: ret double [[T2]]
;
%t1 = fadd double %x, %y
%t2 = fsub double %x, %t1
ret double %t2
}
; X - C --> X + (-C)
define float @constant_op1(float %x, float %y) {
; CHECK-LABEL: @constant_op1(
; CHECK-NEXT: [[R:%.*]] = fadd float [[X:%.*]], -4.200000e+01
; CHECK-NEXT: ret float [[R]]
;
%r = fsub float %x, 42.0
ret float %r
}
define <2 x float> @constant_op1_vec(<2 x float> %x, <2 x float> %y) {
; CHECK-LABEL: @constant_op1_vec(
; CHECK-NEXT: [[R:%.*]] = fadd <2 x float> [[X:%.*]], <float -4.200000e+01, float 4.200000e+01>
; CHECK-NEXT: ret <2 x float> [[R]]
;
%r = fsub <2 x float> %x, <float 42.0, float -42.0>
ret <2 x float> %r
}
define <2 x float> @constant_op1_vec_undef(<2 x float> %x, <2 x float> %y) {
; CHECK-LABEL: @constant_op1_vec_undef(
; CHECK-NEXT: [[R:%.*]] = fadd <2 x float> [[X:%.*]], <float 0x7FF8000000000000, float 4.200000e+01>
; CHECK-NEXT: ret <2 x float> [[R]]
;
%r = fsub <2 x float> %x, <float undef, float -42.0>
ret <2 x float> %r
}
; X - (-Y) --> X + Y
define float @neg_op1(float %x, float %y) {
; CHECK-LABEL: @neg_op1(
; CHECK-NEXT: [[R:%.*]] = fadd float [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: ret float [[R]]
;
%negy = fsub float -0.0, %y
%r = fsub float %x, %negy
ret float %r
}
define <2 x float> @neg_op1_vec(<2 x float> %x, <2 x float> %y) {
; CHECK-LABEL: @neg_op1_vec(
; CHECK-NEXT: [[R:%.*]] = fadd <2 x float> [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: ret <2 x float> [[R]]
;
%negy = fsub <2 x float> <float -0.0, float -0.0>, %y
%r = fsub <2 x float> %x, %negy
ret <2 x float> %r
}
define <2 x float> @neg_op1_vec_undef(<2 x float> %x, <2 x float> %y) {
; CHECK-LABEL: @neg_op1_vec_undef(
; CHECK-NEXT: [[R:%.*]] = fadd <2 x float> [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: ret <2 x float> [[R]]
;
%negy = fsub <2 x float> <float -0.0, float undef>, %y
%r = fsub <2 x float> %x, %negy
ret <2 x float> %r
}