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[InstCombine] add tests for icmp with add nsw; NFC 

llvm-svn: 294601
This commit is contained in:
Sanjay Patel 2017-02-09 18:12:39 +00:00
parent ac7c2ef580
commit b36e1f0223
1 changed files with 123 additions and 0 deletions
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123
llvm/test/Transforms/InstCombine/icmp-add.ll
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@ -83,6 +83,93 @@ define <2 x i1> @test4vec(<2 x i32> %a) {
ret <2 x i1> %c
}
; icmp Pred (add nsw X, C2), C --> icmp Pred X, (C - C2), when C - C2 does not overflow.
; This becomes equality because it's at the limit.
define i1 @nsw_slt1(i8 %a) {
; CHECK-LABEL: @nsw_slt1(
; CHECK-NEXT: [[B:%.*]] = add nsw i8 %a, 100
; CHECK-NEXT: [[C:%.*]] = icmp slt i8 [[B]], -27
; CHECK-NEXT: ret i1 [[C]]
;
%b = add nsw i8 %a, 100
%c = icmp slt i8 %b, -27
ret i1 %c
}
; icmp Pred (add nsw X, C2), C --> icmp Pred X, (C - C2), when C - C2 does not overflow.
; This becomes equality because it's at the limit.
define i1 @nsw_slt2(i8 %a) {
; CHECK-LABEL: @nsw_slt2(
; CHECK-NEXT: [[B:%.*]] = add nsw i8 %a, -100
; CHECK-NEXT: [[C:%.*]] = icmp slt i8 [[B]], 27
; CHECK-NEXT: ret i1 [[C]]
;
%b = add nsw i8 %a, -100
%c = icmp slt i8 %b, 27
ret i1 %c
}
; icmp Pred (add nsw X, C2), C --> icmp Pred X, (C - C2), when C - C2 does not overflow.
; Less than the limit, so the predicate doesn't change.
define i1 @nsw_slt3(i8 %a) {
; CHECK-LABEL: @nsw_slt3(
; CHECK-NEXT: [[B:%.*]] = add nsw i8 %a, 100
; CHECK-NEXT: [[C:%.*]] = icmp slt i8 [[B]], -26
; CHECK-NEXT: ret i1 [[C]]
;
%b = add nsw i8 %a, 100
%c = icmp slt i8 %b, -26
ret i1 %c
}
; icmp Pred (add nsw X, C2), C --> icmp Pred X, (C - C2), when C - C2 does not overflow.
; Less than the limit, so the predicate doesn't change.
define i1 @nsw_slt4(i8 %a) {
; CHECK-LABEL: @nsw_slt4(
; CHECK-NEXT: [[B:%.*]] = add nsw i8 %a, -100
; CHECK-NEXT: [[C:%.*]] = icmp slt i8 [[B]], 26
; CHECK-NEXT: ret i1 [[C]]
;
%b = add nsw i8 %a, -100
%c = icmp slt i8 %b, 26
ret i1 %c
}
; icmp Pred (add nsw X, C2), C --> icmp Pred X, (C - C2), when C - C2 does not overflow.
; Try sgt to make sure that works too.
define i1 @nsw_sgt1(i8 %a) {
; CHECK-LABEL: @nsw_sgt1(
; CHECK-NEXT: [[B:%.*]] = add nsw i8 %a, -100
; CHECK-NEXT: [[C:%.*]] = icmp sgt i8 [[B]], 26
; CHECK-NEXT: ret i1 [[C]]
;
%b = add nsw i8 %a, -100
%c = icmp sgt i8 %b, 26
ret i1 %c
}
; icmp Pred (add nsw X, C2), C --> icmp Pred X, (C - C2), when C - C2 does not overflow.
; Try a vector type to make sure that works too.
define <2 x i1> @nsw_sgt2_splat_vec(<2 x i8> %a) {
; CHECK-LABEL: @nsw_sgt2_splat_vec(
; CHECK-NEXT: [[B:%.*]] = add nsw <2 x i8> %a, <i8 100, i8 100>
; CHECK-NEXT: [[C:%.*]] = icmp sgt <2 x i8> [[B]], <i8 -26, i8 -26>
; CHECK-NEXT: ret <2 x i1> [[C]]
;
%b = add nsw <2 x i8> %a, <i8 100, i8 100>
%c = icmp sgt <2 x i8> %b, <i8 -26, i8 -26>
ret <2 x i1> %c
}
; icmp Pred (add nsw X, C2), C --> icmp Pred X, (C - C2), when C - C2 does not overflow.
; Comparison with 0 doesn't need special-casing.
define i1 @slt_zero_add_nsw(i32 %a) {
; CHECK-LABEL: @slt_zero_add_nsw(
; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 %a, -1
@ -106,6 +193,42 @@ define <2 x i1> @slt_zero_add_nsw_splat_vec(<2 x i8> %a) {
ret <2 x i1> %cmp
}
; Test the edges - instcombine should not interfere with simplification to constants.
; Constant subtraction does not overflow, but this is false.
define i1 @nsw_slt3_ov_no(i8 %a) {
; CHECK-LABEL: @nsw_slt3_ov_no(
; CHECK-NEXT: ret i1 false
;
%b = add nsw i8 %a, 100
%c = icmp slt i8 %b, -28
ret i1 %c
}
; Test the edges - instcombine should not interfere with simplification to constants.
; Constant subtraction overflows. This is false.
define i1 @nsw_slt4_ov(i8 %a) {
; CHECK-LABEL: @nsw_slt4_ov(
; CHECK-NEXT: ret i1 false
;
%b = add nsw i8 %a, 100
%c = icmp slt i8 %b, -29
ret i1 %c
}
; Test the edges - instcombine should not interfere with simplification to constants.
; Constant subtraction overflows. This is true.
define i1 @nsw_slt5_ov(i8 %a) {
; CHECK-LABEL: @nsw_slt5_ov(
; CHECK-NEXT: ret i1 true
;
%b = add nsw i8 %a, -100
%c = icmp slt i8 %b, 28
ret i1 %c
}
; FIXME: InstCombine should not lose wrapping information by changing the add to xor.
define i1 @slt_zero_add_nsw_signbit(i8 %x) {