[InstSimplify] add tests to show missing/broken fadd folds (PR27151, PR26958); NFC
llvm-svn: 327554
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@ -46,41 +46,91 @@ define float @no_mul_zero_3(float %a) {
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ret float %b
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}
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; fadd [nnan ninf] X, (fsub [nnan ninf] 0, X) ==> 0
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; where nnan and ninf have to occur at least once somewhere in this
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; expression
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define float @fadd_fsub_0(float %a) {
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; CHECK-LABEL: @fadd_fsub_0(
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; CHECK-NEXT: [[NOFOLD:%.*]] = fsub float 0.000000e+00, [[A:%.*]]
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; CHECK-NEXT: [[NO_ZERO:%.*]] = fadd nnan float [[NOFOLD]], [[A]]
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; CHECK-NEXT: ret float [[NO_ZERO]]
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; FIXME: -X + X --> 0.0 (with nnan on the fadd)
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define float @fadd_fnegx(float %x) {
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; CHECK-LABEL: @fadd_fnegx(
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; CHECK-NEXT: [[NEGX:%.*]] = fsub float -0.000000e+00, [[X:%.*]]
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; CHECK-NEXT: [[R:%.*]] = fadd nnan float [[NEGX]], [[X]]
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; CHECK-NEXT: ret float [[R]]
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;
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; X + -X ==> 0
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%t1 = fsub nnan ninf float 0.0, %a
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%zero1 = fadd nnan ninf float %t1, %a
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%negx = fsub float -0.0, %x
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%r = fadd nnan float %negx, %x
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ret float %r
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}
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%t2 = fsub nnan float 0.0, %a
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%zero2 = fadd ninf float %t2, %a
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; FIXME: X + -X --> 0.0 (with nnan on the fadd)
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%t3 = fsub nnan ninf float 0.0, %a
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%zero3 = fadd float %t3, %a
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define <2 x float> @fadd_fnegx_commute_vec(<2 x float> %x) {
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; CHECK-LABEL: @fadd_fnegx_commute_vec(
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; CHECK-NEXT: [[NEGX:%.*]] = fsub <2 x float> <float -0.000000e+00, float -0.000000e+00>, [[X:%.*]]
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; CHECK-NEXT: [[R:%.*]] = fadd nnan <2 x float> [[X]], [[NEGX]]
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; CHECK-NEXT: ret <2 x float> [[R]]
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;
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%negx = fsub <2 x float> <float -0.0, float -0.0>, %x
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%r = fadd nnan <2 x float> %x, %negx
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ret <2 x float> %r
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}
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%t4 = fsub float 0.0, %a
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%zero4 = fadd nnan ninf float %t4, %a
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; FIXME: Could be NaN.
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; https://bugs.llvm.org/show_bug.cgi?id=26958
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; https://bugs.llvm.org/show_bug.cgi?id=27151
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; Dont fold this
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%nofold = fsub float 0.0, %a
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%no_zero = fadd nnan float %nofold, %a
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define float @fadd_fneg_nan(float %x) {
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; CHECK-LABEL: @fadd_fneg_nan(
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; CHECK-NEXT: ret float 0.000000e+00
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;
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%t = fsub nnan float -0.0, %x
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%could_be_nan = fadd ninf float %t, %x
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ret float %could_be_nan
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}
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; Coalesce the folded zeros
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%zero5 = fadd float %zero1, %zero2
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%zero6 = fadd float %zero3, %zero4
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%zero7 = fadd float %zero5, %zero6
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; FIXME: Could be NaN.
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; Should get folded
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%ret = fadd nsz float %no_zero, %zero7
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define float @fadd_fneg_nan_commute(float %x) {
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; CHECK-LABEL: @fadd_fneg_nan_commute(
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; CHECK-NEXT: ret float 0.000000e+00
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;
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%t = fsub nnan ninf float -0.0, %x
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%could_be_nan = fadd float %x, %t
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ret float %could_be_nan
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}
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ret float %ret
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; X + (0.0 - X) --> 0.0 (with nnan on the fadd)
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define float @fadd_fsub_nnan_ninf(float %x) {
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; CHECK-LABEL: @fadd_fsub_nnan_ninf(
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; CHECK-NEXT: ret float 0.000000e+00
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;
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%sub = fsub float 0.0, %x
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%zero = fadd nnan ninf float %x, %sub
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ret float %zero
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}
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; (0.0 - X) + X --> 0.0 (with nnan on the fadd)
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define <2 x float> @fadd_fsub_nnan_ninf_commute_vec(<2 x float> %x) {
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; CHECK-LABEL: @fadd_fsub_nnan_ninf_commute_vec(
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; CHECK-NEXT: ret <2 x float> zeroinitializer
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;
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%sub = fsub <2 x float> zeroinitializer, %x
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%zero = fadd nnan ninf <2 x float> %sub, %x
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ret <2 x float> %zero
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}
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; FIXME: Do fold this.
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; 'ninf' is not required because 'nnan' allows us to assume
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; that X is not INF/-INF (adding opposite INFs would be NaN).
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define float @fadd_fsub_nnan(float %x) {
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; CHECK-LABEL: @fadd_fsub_nnan(
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; CHECK-NEXT: [[SUB:%.*]] = fsub float 0.000000e+00, [[X:%.*]]
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; CHECK-NEXT: [[ZERO:%.*]] = fadd nnan float [[SUB]], [[X]]
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; CHECK-NEXT: ret float [[ZERO]]
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;
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%sub = fsub float 0.0, %x
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%zero = fadd nnan float %sub, %x
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ret float %zero
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}
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; fsub nnan x, x ==> 0.0
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