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Sanjay Patel 639da4fda8 [ValueTracking] fix CannotBeNegativeZero() to disregard 'nsz' FMF
The 'nsz' flag is different than 'nnan' or 'ninf' in that it does not create poison.
Make that explicit in the LangRef and fix ValueTracking analysis that misinterpreted
the definition.

This manifests as bugs in InstSimplify shown in the test diffs and as discussed in
PR45778:
https://bugs.llvm.org/show_bug.cgi?id=45778

Differential Revision: https://reviews.llvm.org/D79422
2020-05-05 16:04:59 -04:00

531 lines
15 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -instsimplify -S | FileCheck %s
;; x * 0 ==> 0 when no-nans and no-signed-zero
define float @mul_zero_1(float %a) {
; CHECK-LABEL: @mul_zero_1(
; CHECK-NEXT: ret float 0.000000e+00
;
%b = fmul nsz nnan float %a, 0.0
ret float %b
}
define float @mul_zero_2(float %a) {
; CHECK-LABEL: @mul_zero_2(
; CHECK-NEXT: ret float 0.000000e+00
;
%b = fmul fast float 0.0, %a
ret float %b
}
define <2 x float> @mul_zero_nsz_nnan_vec_undef(<2 x float> %a) {
; CHECK-LABEL: @mul_zero_nsz_nnan_vec_undef(
; CHECK-NEXT: ret <2 x float> zeroinitializer
;
%b = fmul nsz nnan <2 x float> %a, <float 0.0, float undef>
ret <2 x float> %b
}
;; x * 0 =/=> 0 when there could be nans or -0
define float @no_mul_zero_1(float %a) {
; CHECK-LABEL: @no_mul_zero_1(
; CHECK-NEXT: [[B:%.*]] = fmul nsz float [[A:%.*]], 0.000000e+00
; CHECK-NEXT: ret float [[B]]
;
%b = fmul nsz float %a, 0.0
ret float %b
}
define float @no_mul_zero_2(float %a) {
; CHECK-LABEL: @no_mul_zero_2(
; CHECK-NEXT: [[B:%.*]] = fmul nnan float [[A:%.*]], 0.000000e+00
; CHECK-NEXT: ret float [[B]]
;
%b = fmul nnan float %a, 0.0
ret float %b
}
define float @no_mul_zero_3(float %a) {
; CHECK-LABEL: @no_mul_zero_3(
; CHECK-NEXT: [[B:%.*]] = fmul float [[A:%.*]], 0.000000e+00
; CHECK-NEXT: ret float [[B]]
;
%b = fmul float %a, 0.0
ret float %b
}
; -X + X --> 0.0 (with nnan on the fadd)
define float @fadd_binary_fnegx(float %x) {
; CHECK-LABEL: @fadd_binary_fnegx(
; CHECK-NEXT: ret float 0.000000e+00
;
%negx = fsub float -0.0, %x
%r = fadd nnan float %negx, %x
ret float %r
}
define float @fadd_unary_fnegx(float %x) {
; CHECK-LABEL: @fadd_unary_fnegx(
; CHECK-NEXT: ret float 0.000000e+00
;
%negx = fneg float %x
%r = fadd nnan float %negx, %x
ret float %r
}
; X + -X --> 0.0 (with nnan on the fadd)
define <2 x float> @fadd_binary_fnegx_commute_vec(<2 x float> %x) {
; CHECK-LABEL: @fadd_binary_fnegx_commute_vec(
; CHECK-NEXT: ret <2 x float> zeroinitializer
;
%negx = fsub <2 x float> <float -0.0, float -0.0>, %x
%r = fadd nnan <2 x float> %x, %negx
ret <2 x float> %r
}
define <2 x float> @fadd_unary_fnegx_commute_vec(<2 x float> %x) {
; CHECK-LABEL: @fadd_unary_fnegx_commute_vec(
; CHECK-NEXT: ret <2 x float> zeroinitializer
;
%negx = fneg <2 x float> %x
%r = fadd nnan <2 x float> %x, %negx
ret <2 x float> %r
}
define <2 x float> @fadd_fnegx_commute_vec_undef(<2 x float> %x) {
; CHECK-LABEL: @fadd_fnegx_commute_vec_undef(
; CHECK-NEXT: ret <2 x float> zeroinitializer
;
%negx = fsub <2 x float> <float undef, float -0.0>, %x
%r = fadd nnan <2 x float> %x, %negx
ret <2 x float> %r
}
; https://bugs.llvm.org/show_bug.cgi?id=26958
; https://bugs.llvm.org/show_bug.cgi?id=27151
define float @fadd_binary_fneg_nan(float %x) {
; CHECK-LABEL: @fadd_binary_fneg_nan(
; CHECK-NEXT: [[T:%.*]] = fsub nnan float -0.000000e+00, [[X:%.*]]
; CHECK-NEXT: [[COULD_BE_NAN:%.*]] = fadd ninf float [[T]], [[X]]
; CHECK-NEXT: ret float [[COULD_BE_NAN]]
;
%t = fsub nnan float -0.0, %x
%could_be_nan = fadd ninf float %t, %x
ret float %could_be_nan
}
define float @fadd_unary_fneg_nan(float %x) {
; CHECK-LABEL: @fadd_unary_fneg_nan(
; CHECK-NEXT: [[T:%.*]] = fneg nnan float [[X:%.*]]
; CHECK-NEXT: [[COULD_BE_NAN:%.*]] = fadd ninf float [[T]], [[X]]
; CHECK-NEXT: ret float [[COULD_BE_NAN]]
;
%t = fneg nnan float %x
%could_be_nan = fadd ninf float %t, %x
ret float %could_be_nan
}
define float @fadd_binary_fneg_nan_commute(float %x) {
; CHECK-LABEL: @fadd_binary_fneg_nan_commute(
; CHECK-NEXT: [[T:%.*]] = fsub nnan ninf float -0.000000e+00, [[X:%.*]]
; CHECK-NEXT: [[COULD_BE_NAN:%.*]] = fadd float [[X]], [[T]]
; CHECK-NEXT: ret float [[COULD_BE_NAN]]
;
%t = fsub nnan ninf float -0.0, %x
%could_be_nan = fadd float %x, %t
ret float %could_be_nan
}
define float @fadd_unary_fneg_nan_commute(float %x) {
; CHECK-LABEL: @fadd_unary_fneg_nan_commute(
; CHECK-NEXT: [[T:%.*]] = fneg nnan ninf float [[X:%.*]]
; CHECK-NEXT: [[COULD_BE_NAN:%.*]] = fadd float [[X]], [[T]]
; CHECK-NEXT: ret float [[COULD_BE_NAN]]
;
%t = fneg nnan ninf float %x
%could_be_nan = fadd float %x, %t
ret float %could_be_nan
}
; X + (0.0 - X) --> 0.0 (with nnan on the fadd)
define float @fadd_fsub_nnan_ninf(float %x) {
; CHECK-LABEL: @fadd_fsub_nnan_ninf(
; CHECK-NEXT: ret float 0.000000e+00
;
%sub = fsub float 0.0, %x
%zero = fadd nnan ninf float %x, %sub
ret float %zero
}
; (0.0 - X) + X --> 0.0 (with nnan on the fadd)
define <2 x float> @fadd_fsub_nnan_ninf_commute_vec(<2 x float> %x) {
; CHECK-LABEL: @fadd_fsub_nnan_ninf_commute_vec(
; CHECK-NEXT: ret <2 x float> zeroinitializer
;
%sub = fsub <2 x float> zeroinitializer, %x
%zero = fadd nnan ninf <2 x float> %sub, %x
ret <2 x float> %zero
}
; 'ninf' is not required because 'nnan' allows us to assume
; that X is not INF or -INF (adding opposite INFs would be NaN).
define float @fadd_fsub_nnan(float %x) {
; CHECK-LABEL: @fadd_fsub_nnan(
; CHECK-NEXT: ret float 0.000000e+00
;
%sub = fsub float 0.0, %x
%zero = fadd nnan float %sub, %x
ret float %zero
}
; fsub nnan x, x ==> 0.0
define float @fsub_x_x(float %a) {
; CHECK-LABEL: @fsub_x_x(
; CHECK-NEXT: [[NO_ZERO1:%.*]] = fsub ninf float [[A:%.*]], [[A]]
; CHECK-NEXT: [[NO_ZERO2:%.*]] = fsub float [[A]], [[A]]
; CHECK-NEXT: [[NO_ZERO:%.*]] = fadd float [[NO_ZERO1]], [[NO_ZERO2]]
; CHECK-NEXT: ret float [[NO_ZERO]]
;
; X - X ==> 0
%zero1 = fsub nnan float %a, %a
; Dont fold
%no_zero1 = fsub ninf float %a, %a
%no_zero2 = fsub float %a, %a
%no_zero = fadd float %no_zero1, %no_zero2
; Should get folded
%ret = fadd nsz float %no_zero, %zero1
ret float %ret
}
; fsub nsz 0.0, (fsub 0.0, X) ==> X
define float @fsub_0_0_x(float %a) {
; CHECK-LABEL: @fsub_0_0_x(
; CHECK-NEXT: ret float [[A:%.*]]
;
%t1 = fsub float 0.0, %a
%ret = fsub nsz float 0.0, %t1
ret float %ret
}
; fsub nsz 0.0, (fneg X) ==> X
define float @fneg_x(float %a) {
; CHECK-LABEL: @fneg_x(
; CHECK-NEXT: ret float [[A:%.*]]
;
%t1 = fneg float %a
%ret = fsub nsz float 0.0, %t1
ret float %ret
}
define <2 x float> @fsub_0_0_x_vec_undef1(<2 x float> %a) {
; CHECK-LABEL: @fsub_0_0_x_vec_undef1(
; CHECK-NEXT: ret <2 x float> [[A:%.*]]
;
%t1 = fsub <2 x float> <float 0.0, float undef>, %a
%ret = fsub nsz <2 x float> zeroinitializer, %t1
ret <2 x float> %ret
}
define <2 x float> @fneg_x_vec_undef1(<2 x float> %a) {
; CHECK-LABEL: @fneg_x_vec_undef1(
; CHECK-NEXT: ret <2 x float> [[A:%.*]]
;
%t1 = fneg <2 x float> %a
%ret = fsub nsz <2 x float> <float 0.0, float undef>, %t1
ret <2 x float> %ret
}
define <2 x float> @fsub_0_0_x_vec_undef2(<2 x float> %a) {
; CHECK-LABEL: @fsub_0_0_x_vec_undef2(
; CHECK-NEXT: ret <2 x float> [[A:%.*]]
;
%t1 = fsub <2 x float> zeroinitializer, %a
%ret = fsub nsz <2 x float> <float undef, float -0.0>, %t1
ret <2 x float> %ret
}
; fadd nsz X, 0 ==> X
define <2 x float> @fadd_zero_nsz_vec(<2 x float> %x) {
; CHECK-LABEL: @fadd_zero_nsz_vec(
; CHECK-NEXT: ret <2 x float> [[X:%.*]]
;
%r = fadd nsz <2 x float> %x, zeroinitializer
ret <2 x float> %r
}
define <2 x float> @fadd_zero_nsz_vec_undef(<2 x float> %x) {
; CHECK-LABEL: @fadd_zero_nsz_vec_undef(
; CHECK-NEXT: ret <2 x float> [[X:%.*]]
;
%r = fadd nsz <2 x float> %x, <float 0.0, float undef>
ret <2 x float> %r
}
define float @nofold_fadd_x_0(float %a) {
; CHECK-LABEL: @nofold_fadd_x_0(
; CHECK-NEXT: [[NO_ZERO1:%.*]] = fadd ninf float [[A:%.*]], 0.000000e+00
; CHECK-NEXT: [[NO_ZERO2:%.*]] = fadd nnan float [[A]], 0.000000e+00
; CHECK-NEXT: [[NO_ZERO:%.*]] = fadd float [[NO_ZERO1]], [[NO_ZERO2]]
; CHECK-NEXT: ret float [[NO_ZERO]]
;
; Dont fold
%no_zero1 = fadd ninf float %a, 0.0
%no_zero2 = fadd nnan float %a, 0.0
%no_zero = fadd float %no_zero1, %no_zero2
ret float %no_zero
}
define float @fold_fadd_nsz_x_0(float %a) {
; CHECK-LABEL: @fold_fadd_nsz_x_0(
; CHECK-NEXT: ret float [[A:%.*]]
;
%add = fadd nsz float %a, 0.0
ret float %add
}
; 'nsz' does not guarantee that -0.0 does not occur, so this does not simplify.
define float @fold_fadd_cannot_be_neg0_nsz_src_x_0(float %a, float %b) {
; CHECK-LABEL: @fold_fadd_cannot_be_neg0_nsz_src_x_0(
; CHECK-NEXT: [[NSZ:%.*]] = fmul nsz float [[A:%.*]], [[B:%.*]]
; CHECK-NEXT: [[ADD:%.*]] = fadd float [[NSZ]], 0.000000e+00
; CHECK-NEXT: ret float [[ADD]]
;
%nsz = fmul nsz float %a, %b
%add = fadd float %nsz, 0.0
ret float %add
}
define float @fold_fadd_cannot_be_neg0_fabs_src_x_0(float %a) {
; CHECK-LABEL: @fold_fadd_cannot_be_neg0_fabs_src_x_0(
; CHECK-NEXT: [[FABS:%.*]] = call float @llvm.fabs.f32(float [[A:%.*]])
; CHECK-NEXT: ret float [[FABS]]
;
%fabs = call float @llvm.fabs.f32(float %a)
%add = fadd float %fabs, 0.0
ret float %add
}
; 'nsz' does not guarantee that -0.0 does not occur, so this does not simplify.
define float @fold_fadd_cannot_be_neg0_sqrt_nsz_src_x_0(float %a, float %b) {
; CHECK-LABEL: @fold_fadd_cannot_be_neg0_sqrt_nsz_src_x_0(
; CHECK-NEXT: [[NSZ:%.*]] = fmul nsz float [[A:%.*]], [[B:%.*]]
; CHECK-NEXT: [[SQRT:%.*]] = call float @llvm.sqrt.f32(float [[NSZ]])
; CHECK-NEXT: [[ADD:%.*]] = fadd float [[SQRT]], 0.000000e+00
; CHECK-NEXT: ret float [[ADD]]
;
%nsz = fmul nsz float %a, %b
%sqrt = call float @llvm.sqrt.f32(float %nsz)
%add = fadd float %sqrt, 0.0
ret float %add
}
; 'nsz' does not guarantee that -0.0 does not occur, so this does not simplify.
define float @fold_fadd_cannot_be_neg0_canonicalize_nsz_src_x_0(float %a, float %b) {
; CHECK-LABEL: @fold_fadd_cannot_be_neg0_canonicalize_nsz_src_x_0(
; CHECK-NEXT: [[NSZ:%.*]] = fmul nsz float [[A:%.*]], [[B:%.*]]
; CHECK-NEXT: [[CANON:%.*]] = call float @llvm.canonicalize.f32(float [[NSZ]])
; CHECK-NEXT: [[ADD:%.*]] = fadd float [[CANON]], 0.000000e+00
; CHECK-NEXT: ret float [[ADD]]
;
%nsz = fmul nsz float %a, %b
%canon = call float @llvm.canonicalize.f32(float %nsz)
%add = fadd float %canon, 0.0
ret float %add
}
; fdiv nsz nnan 0, X ==> 0
; 0 / X -> 0
define double @fdiv_zero_by_x(double %x) {
; CHECK-LABEL: @fdiv_zero_by_x(
; CHECK-NEXT: ret double 0.000000e+00
;
%r = fdiv nnan nsz double 0.0, %x
ret double %r
}
define <2 x double> @fdiv_zero_by_x_vec_undef(<2 x double> %x) {
; CHECK-LABEL: @fdiv_zero_by_x_vec_undef(
; CHECK-NEXT: ret <2 x double> zeroinitializer
;
%r = fdiv nnan nsz <2 x double> <double 0.0, double undef>, %x
ret <2 x double> %r
}
; 0 % X -> 0
; nsz is not necessary - frem result always has the sign of the dividend
define double @frem_zero_by_x(double %x) {
; CHECK-LABEL: @frem_zero_by_x(
; CHECK-NEXT: ret double 0.000000e+00
;
%r = frem nnan double 0.0, %x
ret double %r
}
define <2 x double> @frem_poszero_by_x_vec_undef(<2 x double> %x) {
; CHECK-LABEL: @frem_poszero_by_x_vec_undef(
; CHECK-NEXT: ret <2 x double> zeroinitializer
;
%r = frem nnan <2 x double> <double 0.0, double undef>, %x
ret <2 x double> %r
}
; -0 % X -> -0
; nsz is not necessary - frem result always has the sign of the dividend
define double @frem_negzero_by_x(double %x) {
; CHECK-LABEL: @frem_negzero_by_x(
; CHECK-NEXT: ret double -0.000000e+00
;
%r = frem nnan double -0.0, %x
ret double %r
}
define <2 x double> @frem_negzero_by_x_vec_undef(<2 x double> %x) {
; CHECK-LABEL: @frem_negzero_by_x_vec_undef(
; CHECK-NEXT: ret <2 x double> <double -0.000000e+00, double -0.000000e+00>
;
%r = frem nnan <2 x double> <double undef, double -0.0>, %x
ret <2 x double> %r
}
define float @fdiv_self(float %f) {
; CHECK-LABEL: @fdiv_self(
; CHECK-NEXT: ret float 1.000000e+00
;
%div = fdiv nnan float %f, %f
ret float %div
}
define float @fdiv_self_invalid(float %f) {
; CHECK-LABEL: @fdiv_self_invalid(
; CHECK-NEXT: [[DIV:%.*]] = fdiv float [[F:%.*]], [[F]]
; CHECK-NEXT: ret float [[DIV]]
;
%div = fdiv float %f, %f
ret float %div
}
define float @fdiv_neg1(float %f) {
; CHECK-LABEL: @fdiv_neg1(
; CHECK-NEXT: ret float -1.000000e+00
;
%neg = fsub fast float -0.000000e+00, %f
%div = fdiv nnan float %neg, %f
ret float %div
}
define float @fdiv_neg2(float %f) {
; CHECK-LABEL: @fdiv_neg2(
; CHECK-NEXT: ret float -1.000000e+00
;
%neg = fsub fast float 0.000000e+00, %f
%div = fdiv nnan float %neg, %f
ret float %div
}
define float @fdiv_neg_invalid(float %f) {
; CHECK-LABEL: @fdiv_neg_invalid(
; CHECK-NEXT: [[NEG:%.*]] = fsub fast float -0.000000e+00, [[F:%.*]]
; CHECK-NEXT: [[DIV:%.*]] = fdiv float [[NEG]], [[F]]
; CHECK-NEXT: ret float [[DIV]]
;
%neg = fsub fast float -0.000000e+00, %f
%div = fdiv float %neg, %f
ret float %div
}
define float @fdiv_neg_swapped1(float %f) {
; CHECK-LABEL: @fdiv_neg_swapped1(
; CHECK-NEXT: ret float -1.000000e+00
;
%neg = fsub float -0.000000e+00, %f
%div = fdiv nnan float %f, %neg
ret float %div
}
define float @fdiv_neg_swapped2(float %f) {
; CHECK-LABEL: @fdiv_neg_swapped2(
; CHECK-NEXT: ret float -1.000000e+00
;
%neg = fsub float 0.000000e+00, %f
%div = fdiv nnan float %f, %neg
ret float %div
}
define <2 x float> @fdiv_neg_vec_undef_elt(<2 x float> %f) {
; CHECK-LABEL: @fdiv_neg_vec_undef_elt(
; CHECK-NEXT: ret <2 x float> <float -1.000000e+00, float -1.000000e+00>
;
%neg = fsub <2 x float> <float 0.0, float undef>, %f
%div = fdiv nnan <2 x float> %f, %neg
ret <2 x float> %div
}
; PR21126: http://llvm.org/bugs/show_bug.cgi?id=21126
; With loose math, sqrt(X) * sqrt(X) is just X.
declare double @llvm.sqrt.f64(double)
define double @sqrt_squared(double %f) {
; CHECK-LABEL: @sqrt_squared(
; CHECK-NEXT: ret double [[F:%.*]]
;
%sqrt = call double @llvm.sqrt.f64(double %f)
%mul = fmul reassoc nnan nsz double %sqrt, %sqrt
ret double %mul
}
; Negative tests for the above transform: we need all 3 of those flags.
define double @sqrt_squared_not_fast_enough1(double %f) {
; CHECK-LABEL: @sqrt_squared_not_fast_enough1(
; CHECK-NEXT: [[SQRT:%.*]] = call double @llvm.sqrt.f64(double [[F:%.*]])
; CHECK-NEXT: [[MUL:%.*]] = fmul nnan nsz double [[SQRT]], [[SQRT]]
; CHECK-NEXT: ret double [[MUL]]
;
%sqrt = call double @llvm.sqrt.f64(double %f)
%mul = fmul nnan nsz double %sqrt, %sqrt
ret double %mul
}
define double @sqrt_squared_not_fast_enough2(double %f) {
; CHECK-LABEL: @sqrt_squared_not_fast_enough2(
; CHECK-NEXT: [[SQRT:%.*]] = call double @llvm.sqrt.f64(double [[F:%.*]])
; CHECK-NEXT: [[MUL:%.*]] = fmul reassoc nnan double [[SQRT]], [[SQRT]]
; CHECK-NEXT: ret double [[MUL]]
;
%sqrt = call double @llvm.sqrt.f64(double %f)
%mul = fmul reassoc nnan double %sqrt, %sqrt
ret double %mul
}
define double @sqrt_squared_not_fast_enough3(double %f) {
; CHECK-LABEL: @sqrt_squared_not_fast_enough3(
; CHECK-NEXT: [[SQRT:%.*]] = call double @llvm.sqrt.f64(double [[F:%.*]])
; CHECK-NEXT: [[MUL:%.*]] = fmul reassoc nsz double [[SQRT]], [[SQRT]]
; CHECK-NEXT: ret double [[MUL]]
;
%sqrt = call double @llvm.sqrt.f64(double %f)
%mul = fmul reassoc nsz double %sqrt, %sqrt
ret double %mul
}
declare float @llvm.fabs.f32(float)
declare float @llvm.sqrt.f32(float)
declare float @llvm.canonicalize.f32(float)