; NOTE: Assertions have been autogenerated by utils/update_test_checks.py ; RUN: opt < %s -instcombine -S | FileCheck %s ; PR1949 define i1 @test1(i32 %a) { ; CHECK-LABEL: @test1( ; CHECK-NEXT: [[C:%.*]] = icmp ugt i32 %a, -5 ; CHECK-NEXT: ret i1 [[C]] ; %b = add i32 %a, 4 %c = icmp ult i32 %b, 4 ret i1 %c } define <2 x i1> @test1vec(<2 x i32> %a) { ; CHECK-LABEL: @test1vec( ; CHECK-NEXT: [[C:%.*]] = icmp ugt <2 x i32> %a, ; CHECK-NEXT: ret <2 x i1> [[C]] ; %b = add <2 x i32> %a, %c = icmp ult <2 x i32> %b, ret <2 x i1> %c } define i1 @test2(i32 %a) { ; CHECK-LABEL: @test2( ; CHECK-NEXT: [[C:%.*]] = icmp ult i32 %a, 4 ; CHECK-NEXT: ret i1 [[C]] ; %b = sub i32 %a, 4 %c = icmp ugt i32 %b, -5 ret i1 %c } define <2 x i1> @test2vec(<2 x i32> %a) { ; CHECK-LABEL: @test2vec( ; CHECK-NEXT: [[C:%.*]] = icmp ult <2 x i32> %a, ; CHECK-NEXT: ret <2 x i1> [[C]] ; %b = sub <2 x i32> %a, %c = icmp ugt <2 x i32> %b, ret <2 x i1> %c } define i1 @test3(i32 %a) { ; CHECK-LABEL: @test3( ; CHECK-NEXT: [[C:%.*]] = icmp sgt i32 %a, 2147483643 ; CHECK-NEXT: ret i1 [[C]] ; %b = add i32 %a, 4 %c = icmp slt i32 %b, 2147483652 ret i1 %c } define <2 x i1> @test3vec(<2 x i32> %a) { ; CHECK-LABEL: @test3vec( ; CHECK-NEXT: [[C:%.*]] = icmp sgt <2 x i32> %a, ; CHECK-NEXT: ret <2 x i1> [[C]] ; %b = add <2 x i32> %a, %c = icmp slt <2 x i32> %b, ret <2 x i1> %c } define i1 @test4(i32 %a) { ; CHECK-LABEL: @test4( ; CHECK-NEXT: [[C:%.*]] = icmp slt i32 %a, -4 ; CHECK-NEXT: ret i1 [[C]] ; %b = add i32 %a, 2147483652 %c = icmp sge i32 %b, 4 ret i1 %c } define <2 x i1> @test4vec(<2 x i32> %a) { ; CHECK-LABEL: @test4vec( ; CHECK-NEXT: [[C:%.*]] = icmp slt <2 x i32> %a, ; CHECK-NEXT: ret <2 x i1> [[C]] ; %b = add <2 x i32> %a, %c = icmp sge <2 x i32> %b, 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: [[C:%.*]] = icmp eq i8 %a, -128 ; CHECK-NEXT: ret i1 [[C]] ; %b = add nsw i8 %a, 100 %c = icmp slt i8 %b, -27 ret i1 %c } define <2 x i1> @nsw_slt1_splat_vec(<2 x i8> %a) { ; CHECK-LABEL: @nsw_slt1_splat_vec( ; CHECK-NEXT: [[C:%.*]] = icmp eq <2 x i8> [[A:%.*]], ; CHECK-NEXT: ret <2 x i1> [[C]] ; %b = add nsw <2 x i8> %a, %c = icmp slt <2 x i8> %b, 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_slt2(i8 %a) { ; CHECK-LABEL: @nsw_slt2( ; CHECK-NEXT: [[C:%.*]] = icmp ne i8 %a, 127 ; CHECK-NEXT: ret i1 [[C]] ; %b = add nsw i8 %a, -100 %c = icmp slt i8 %b, 27 ret i1 %c } define <2 x i1> @nsw_slt2_splat_vec(<2 x i8> %a) { ; CHECK-LABEL: @nsw_slt2_splat_vec( ; CHECK-NEXT: [[C:%.*]] = icmp ne <2 x i8> [[A:%.*]], ; CHECK-NEXT: ret <2 x i1> [[C]] ; %b = add nsw <2 x i8> %a, %c = icmp slt <2 x i8> %b, ret <2 x 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: [[C:%.*]] = icmp slt i8 %a, -126 ; 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: [[C:%.*]] = icmp slt i8 %a, 126 ; 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: [[C:%.*]] = icmp eq i8 %a, 127 ; CHECK-NEXT: ret i1 [[C]] ; %b = add nsw i8 %a, -100 %c = icmp sgt i8 %b, 26 ret i1 %c } define <2 x i1> @nsw_sgt1_splat_vec(<2 x i8> %a) { ; CHECK-LABEL: @nsw_sgt1_splat_vec( ; CHECK-NEXT: [[C:%.*]] = icmp eq <2 x i8> [[A:%.*]], ; CHECK-NEXT: ret <2 x i1> [[C]] ; %b = add nsw <2 x i8> %a, %c = icmp sgt <2 x i8> %b, ret <2 x i1> %c } define i1 @nsw_sgt2(i8 %a) { ; CHECK-LABEL: @nsw_sgt2( ; CHECK-NEXT: [[C:%.*]] = icmp sgt i8 [[A:%.*]], -126 ; CHECK-NEXT: ret i1 [[C]] ; %b = add nsw i8 %a, 100 %c = icmp sgt i8 %b, -26 ret i1 %c } define <2 x i1> @nsw_sgt2_splat_vec(<2 x i8> %a) { ; CHECK-LABEL: @nsw_sgt2_splat_vec( ; CHECK-NEXT: [[C:%.*]] = icmp sgt <2 x i8> %a, ; CHECK-NEXT: ret <2 x i1> [[C]] ; %b = add nsw <2 x i8> %a, %c = icmp sgt <2 x i8> %b, 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 ; CHECK-NEXT: ret i1 [[CMP]] ; %add = add nsw i32 %a, 1 %cmp = icmp slt i32 %add, 0 ret i1 %cmp } ; The same fold should work with vectors. define <2 x i1> @slt_zero_add_nsw_splat_vec(<2 x i8> %a) { ; CHECK-LABEL: @slt_zero_add_nsw_splat_vec( ; CHECK-NEXT: [[CMP:%.*]] = icmp slt <2 x i8> %a, ; CHECK-NEXT: ret <2 x i1> [[CMP]] ; %add = add nsw <2 x i8> %a, %cmp = icmp slt <2 x i8> %add, zeroinitializer 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 } ; InstCombine should not thwart this opportunity to simplify completely. define i1 @slt_zero_add_nsw_signbit(i8 %x) { ; CHECK-LABEL: @slt_zero_add_nsw_signbit( ; CHECK-NEXT: ret i1 true ; %y = add nsw i8 %x, -128 %z = icmp slt i8 %y, 0 ret i1 %z } ; InstCombine should not thwart this opportunity to simplify completely. define i1 @slt_zero_add_nuw_signbit(i8 %x) { ; CHECK-LABEL: @slt_zero_add_nuw_signbit( ; CHECK-NEXT: ret i1 true ; %y = add nuw i8 %x, 128 %z = icmp slt i8 %y, 0 ret i1 %z }