; NOTE: Assertions have been autogenerated by utils/update_test_checks.py ; RUN: opt < %s -instsimplify -S | FileCheck %s define i1 @bool_true_or_false(i1 %cond) { ; CHECK-LABEL: @bool_true_or_false( ; CHECK-NEXT: ret i1 [[COND:%.*]] ; %s = select i1 %cond, i1 true, i1 false ret i1 %s } define <2 x i1> @bool_true_or_false_vec(<2 x i1> %cond) { ; CHECK-LABEL: @bool_true_or_false_vec( ; CHECK-NEXT: ret <2 x i1> [[COND:%.*]] ; %s = select <2 x i1> %cond, <2 x i1> <i1 true, i1 true>, <2 x i1> zeroinitializer ret <2 x i1> %s } define <2 x i1> @bool_true_or_false_vec_undef(<2 x i1> %cond) { ; CHECK-LABEL: @bool_true_or_false_vec_undef( ; CHECK-NEXT: ret <2 x i1> [[COND:%.*]] ; %s = select <2 x i1> %cond, <2 x i1> <i1 undef, i1 true>, <2 x i1> <i1 false, i1 undef> ret <2 x i1> %s } define i32 @cond_is_false(i32 %A, i32 %B) { ; CHECK-LABEL: @cond_is_false( ; CHECK-NEXT: ret i32 [[B:%.*]] ; %C = select i1 false, i32 %A, i32 %B ret i32 %C } define i32 @cond_is_true(i32 %A, i32 %B) { ; CHECK-LABEL: @cond_is_true( ; CHECK-NEXT: ret i32 [[A:%.*]] ; %C = select i1 true, i32 %A, i32 %B ret i32 %C } define i32 @equal_arms(i1 %cond, i32 %x) { ; CHECK-LABEL: @equal_arms( ; CHECK-NEXT: ret i32 [[X:%.*]] ; %V = select i1 %cond, i32 %x, i32 %x ret i32 %V } define <2 x i32> @equal_arms_vec(<2 x i1> %cond, <2 x i32> %x) { ; CHECK-LABEL: @equal_arms_vec( ; CHECK-NEXT: ret <2 x i32> [[X:%.*]] ; %V = select <2 x i1> %cond, <2 x i32> %x, <2 x i32> %x ret <2 x i32> %V } define <2 x i32> @equal_arms_vec_undef(<2 x i1> %cond) { ; CHECK-LABEL: @equal_arms_vec_undef( ; CHECK-NEXT: [[V:%.*]] = select <2 x i1> [[COND:%.*]], <2 x i32> <i32 42, i32 undef>, <2 x i32> <i32 undef, i32 42> ; CHECK-NEXT: ret <2 x i32> [[V]] ; %V = select <2 x i1> %cond, <2 x i32> <i32 42, i32 undef>, <2 x i32> <i32 undef, i32 42> ret <2 x i32> %V } define <2 x i8> @vsel_tvec(<2 x i8> %x, <2 x i8> %y) { ; CHECK-LABEL: @vsel_tvec( ; CHECK-NEXT: ret <2 x i8> [[X:%.*]] ; %s = select <2 x i1><i1 true, i1 true>, <2 x i8> %x, <2 x i8> %y ret <2 x i8> %s } define <2 x i8> @vsel_fvec(<2 x i8> %x, <2 x i8> %y) { ; CHECK-LABEL: @vsel_fvec( ; CHECK-NEXT: ret <2 x i8> [[Y:%.*]] ; %s = select <2 x i1><i1 false, i1 false>, <2 x i8> %x, <2 x i8> %y ret <2 x i8> %s } define <2 x i8> @vsel_mixedvec() { ; CHECK-LABEL: @vsel_mixedvec( ; CHECK-NEXT: ret <2 x i8> <i8 0, i8 3> ; %s = select <2 x i1><i1 true, i1 false>, <2 x i8> <i8 0, i8 1>, <2 x i8> <i8 2, i8 3> ret <2 x i8> %s } ; FIXME: Allow for undef elements in a constant vector condition. define <3 x i8> @vsel_undef_true_op(<3 x i8> %x, <3 x i8> %y) { ; CHECK-LABEL: @vsel_undef_true_op( ; CHECK-NEXT: [[S:%.*]] = select <3 x i1> <i1 true, i1 undef, i1 true>, <3 x i8> [[X:%.*]], <3 x i8> [[Y:%.*]] ; CHECK-NEXT: ret <3 x i8> [[S]] ; %s = select <3 x i1><i1 1, i1 undef, i1 1>, <3 x i8> %x, <3 x i8> %y ret <3 x i8> %s } define <3 x i4> @vsel_undef_false_op(<3 x i4> %x, <3 x i4> %y) { ; CHECK-LABEL: @vsel_undef_false_op( ; CHECK-NEXT: [[S:%.*]] = select <3 x i1> <i1 false, i1 undef, i1 undef>, <3 x i4> [[X:%.*]], <3 x i4> [[Y:%.*]] ; CHECK-NEXT: ret <3 x i4> [[S]] ; %s = select <3 x i1><i1 0, i1 undef, i1 undef>, <3 x i4> %x, <3 x i4> %y ret <3 x i4> %s } define i32 @test1(i32 %x) { ; CHECK-LABEL: @test1( ; CHECK-NEXT: ret i32 [[X:%.*]] ; %and = and i32 %x, 1 %cmp = icmp eq i32 %and, 0 %and1 = and i32 %x, -2 %and1.x = select i1 %cmp, i32 %and1, i32 %x ret i32 %and1.x } define i32 @test2(i32 %x) { ; CHECK-LABEL: @test2( ; CHECK-NEXT: ret i32 [[X:%.*]] ; %and = and i32 %x, 1 %cmp = icmp ne i32 %and, 0 %and1 = and i32 %x, -2 %and1.x = select i1 %cmp, i32 %x, i32 %and1 ret i32 %and1.x } define i32 @test3(i32 %x) { ; CHECK-LABEL: @test3( ; CHECK-NEXT: [[AND1:%.*]] = and i32 [[X:%.*]], -2 ; CHECK-NEXT: ret i32 [[AND1]] ; %and = and i32 %x, 1 %cmp = icmp ne i32 %and, 0 %and1 = and i32 %x, -2 %and1.x = select i1 %cmp, i32 %and1, i32 %x ret i32 %and1.x } define i32 @test4(i32 %X) { ; CHECK-LABEL: @test4( ; CHECK-NEXT: [[OR:%.*]] = or i32 [[X:%.*]], -2147483648 ; CHECK-NEXT: ret i32 [[OR]] ; %cmp = icmp slt i32 %X, 0 %or = or i32 %X, -2147483648 %cond = select i1 %cmp, i32 %X, i32 %or ret i32 %cond } ; Same as above, but the compare isn't canonical define i32 @test4noncanon(i32 %X) { ; CHECK-LABEL: @test4noncanon( ; CHECK-NEXT: [[OR:%.*]] = or i32 [[X:%.*]], -2147483648 ; CHECK-NEXT: ret i32 [[OR]] ; %cmp = icmp sle i32 %X, -1 %or = or i32 %X, -2147483648 %cond = select i1 %cmp, i32 %X, i32 %or ret i32 %cond } define i32 @test5(i32 %X) { ; CHECK-LABEL: @test5( ; CHECK-NEXT: ret i32 [[X:%.*]] ; %cmp = icmp slt i32 %X, 0 %or = or i32 %X, -2147483648 %cond = select i1 %cmp, i32 %or, i32 %X ret i32 %cond } define i32 @test6(i32 %X) { ; CHECK-LABEL: @test6( ; CHECK-NEXT: [[AND:%.*]] = and i32 [[X:%.*]], 2147483647 ; CHECK-NEXT: ret i32 [[AND]] ; %cmp = icmp slt i32 %X, 0 %and = and i32 %X, 2147483647 %cond = select i1 %cmp, i32 %and, i32 %X ret i32 %cond } define i32 @test7(i32 %X) { ; CHECK-LABEL: @test7( ; CHECK-NEXT: ret i32 [[X:%.*]] ; %cmp = icmp slt i32 %X, 0 %and = and i32 %X, 2147483647 %cond = select i1 %cmp, i32 %X, i32 %and ret i32 %cond } define i32 @test8(i32 %X) { ; CHECK-LABEL: @test8( ; CHECK-NEXT: ret i32 [[X:%.*]] ; %cmp = icmp sgt i32 %X, -1 %or = or i32 %X, -2147483648 %cond = select i1 %cmp, i32 %X, i32 %or ret i32 %cond } define i32 @test9(i32 %X) { ; CHECK-LABEL: @test9( ; CHECK-NEXT: [[OR:%.*]] = or i32 [[X:%.*]], -2147483648 ; CHECK-NEXT: ret i32 [[OR]] ; %cmp = icmp sgt i32 %X, -1 %or = or i32 %X, -2147483648 %cond = select i1 %cmp, i32 %or, i32 %X ret i32 %cond } ; Same as above, but the compare isn't canonical define i32 @test9noncanon(i32 %X) { ; CHECK-LABEL: @test9noncanon( ; CHECK-NEXT: [[OR:%.*]] = or i32 [[X:%.*]], -2147483648 ; CHECK-NEXT: ret i32 [[OR]] ; %cmp = icmp sge i32 %X, 0 %or = or i32 %X, -2147483648 %cond = select i1 %cmp, i32 %or, i32 %X ret i32 %cond } define i32 @test10(i32 %X) { ; CHECK-LABEL: @test10( ; CHECK-NEXT: ret i32 [[X:%.*]] ; %cmp = icmp sgt i32 %X, -1 %and = and i32 %X, 2147483647 %cond = select i1 %cmp, i32 %and, i32 %X ret i32 %cond } define i32 @test11(i32 %X) { ; CHECK-LABEL: @test11( ; CHECK-NEXT: [[AND:%.*]] = and i32 [[X:%.*]], 2147483647 ; CHECK-NEXT: ret i32 [[AND]] ; %cmp = icmp sgt i32 %X, -1 %and = and i32 %X, 2147483647 %cond = select i1 %cmp, i32 %X, i32 %and ret i32 %cond } define <2 x i8> @test11vec(<2 x i8> %X) { ; CHECK-LABEL: @test11vec( ; CHECK-NEXT: [[AND:%.*]] = and <2 x i8> [[X:%.*]], <i8 127, i8 127> ; CHECK-NEXT: ret <2 x i8> [[AND]] ; %cmp = icmp sgt <2 x i8> %X, <i8 -1, i8 -1> %and = and <2 x i8> %X, <i8 127, i8 127> %sel = select <2 x i1> %cmp, <2 x i8> %X, <2 x i8> %and ret <2 x i8> %sel } define i32 @test12(i32 %X) { ; CHECK-LABEL: @test12( ; CHECK-NEXT: [[AND:%.*]] = and i32 [[X:%.*]], 3 ; CHECK-NEXT: ret i32 [[AND]] ; %cmp = icmp ult i32 %X, 4 %and = and i32 %X, 3 %cond = select i1 %cmp, i32 %X, i32 %and ret i32 %cond } ; Same as above, but the compare isn't canonical define i32 @test12noncanon(i32 %X) { ; CHECK-LABEL: @test12noncanon( ; CHECK-NEXT: [[AND:%.*]] = and i32 [[X:%.*]], 3 ; CHECK-NEXT: ret i32 [[AND]] ; %cmp = icmp ule i32 %X, 3 %and = and i32 %X, 3 %cond = select i1 %cmp, i32 %X, i32 %and ret i32 %cond } define i32 @test13(i32 %X) { ; CHECK-LABEL: @test13( ; CHECK-NEXT: [[AND:%.*]] = and i32 [[X:%.*]], 3 ; CHECK-NEXT: ret i32 [[AND]] ; %cmp = icmp ugt i32 %X, 3 %and = and i32 %X, 3 %cond = select i1 %cmp, i32 %and, i32 %X ret i32 %cond } ; Same as above, but the compare isn't canonical define i32 @test13noncanon(i32 %X) { ; CHECK-LABEL: @test13noncanon( ; CHECK-NEXT: [[AND:%.*]] = and i32 [[X:%.*]], 3 ; CHECK-NEXT: ret i32 [[AND]] ; %cmp = icmp uge i32 %X, 4 %and = and i32 %X, 3 %cond = select i1 %cmp, i32 %and, i32 %X ret i32 %cond } define i32 @select_icmp_and_8_eq_0_or_8(i32 %x) { ; CHECK-LABEL: @select_icmp_and_8_eq_0_or_8( ; CHECK-NEXT: [[OR:%.*]] = or i32 [[X:%.*]], 8 ; CHECK-NEXT: ret i32 [[OR]] ; %and = and i32 %x, 8 %cmp = icmp eq i32 %and, 0 %or = or i32 %x, 8 %sel = select i1 %cmp, i32 %or, i32 %x ret i32 %sel } define i32 @select_icmp_and_8_eq_0_or_8_alt(i32 %x) { ; CHECK-LABEL: @select_icmp_and_8_eq_0_or_8_alt( ; CHECK-NEXT: [[OR:%.*]] = or i32 [[X:%.*]], 8 ; CHECK-NEXT: ret i32 [[OR]] ; %and = and i32 %x, 8 %cmp = icmp ne i32 %and, 0 %or = or i32 %x, 8 %sel = select i1 %cmp, i32 %x, i32 %or ret i32 %sel } define i32 @select_icmp_and_8_ne_0_or_8(i32 %x) { ; CHECK-LABEL: @select_icmp_and_8_ne_0_or_8( ; CHECK-NEXT: ret i32 [[X:%.*]] ; %and = and i32 %x, 8 %cmp = icmp ne i32 %and, 0 %or = or i32 %x, 8 %sel = select i1 %cmp, i32 %or, i32 %x ret i32 %sel } define i32 @select_icmp_and_8_ne_0_or_8_alt(i32 %x) { ; CHECK-LABEL: @select_icmp_and_8_ne_0_or_8_alt( ; CHECK-NEXT: ret i32 [[X:%.*]] ; %and = and i32 %x, 8 %cmp = icmp eq i32 %and, 0 %or = or i32 %x, 8 %sel = select i1 %cmp, i32 %x, i32 %or ret i32 %sel } define i32 @select_icmp_and_8_eq_0_and_not_8(i32 %x) { ; CHECK-LABEL: @select_icmp_and_8_eq_0_and_not_8( ; CHECK-NEXT: [[AND1:%.*]] = and i32 [[X:%.*]], -9 ; CHECK-NEXT: ret i32 [[AND1]] ; %and = and i32 %x, 8 %cmp = icmp eq i32 %and, 0 %and1 = and i32 %x, -9 %sel = select i1 %cmp, i32 %x, i32 %and1 ret i32 %sel } define i32 @select_icmp_and_8_eq_0_and_not_8_alt(i32 %x) { ; CHECK-LABEL: @select_icmp_and_8_eq_0_and_not_8_alt( ; CHECK-NEXT: [[AND1:%.*]] = and i32 [[X:%.*]], -9 ; CHECK-NEXT: ret i32 [[AND1]] ; %and = and i32 %x, 8 %cmp = icmp ne i32 %and, 0 %and1 = and i32 %x, -9 %sel = select i1 %cmp, i32 %and1, i32 %x ret i32 %sel } define i32 @select_icmp_and_8_ne_0_and_not_8(i32 %x) { ; CHECK-LABEL: @select_icmp_and_8_ne_0_and_not_8( ; CHECK-NEXT: ret i32 [[X:%.*]] ; %and = and i32 %x, 8 %cmp = icmp ne i32 %and, 0 %and1 = and i32 %x, -9 %sel = select i1 %cmp, i32 %x, i32 %and1 ret i32 %sel } define i32 @select_icmp_and_8_ne_0_and_not_8_alt(i32 %x) { ; CHECK-LABEL: @select_icmp_and_8_ne_0_and_not_8_alt( ; CHECK-NEXT: ret i32 [[X:%.*]] ; %and = and i32 %x, 8 %cmp = icmp eq i32 %and, 0 %and1 = and i32 %x, -9 %sel = select i1 %cmp, i32 %and1, i32 %x ret i32 %sel } ; PR28466: https://llvm.org/bugs/show_bug.cgi?id=28466 ; Each of the previous 8 patterns has a variant that replaces the ; 'and' with a 'trunc' and the icmp eq/ne with icmp slt/sgt. define i32 @select_icmp_trunc_8_ne_0_or_128(i32 %x) { ; CHECK-LABEL: @select_icmp_trunc_8_ne_0_or_128( ; CHECK-NEXT: [[OR:%.*]] = or i32 [[X:%.*]], 128 ; CHECK-NEXT: ret i32 [[OR]] ; %trunc = trunc i32 %x to i8 %cmp = icmp sgt i8 %trunc, -1 %or = or i32 %x, 128 %sel = select i1 %cmp, i32 %or, i32 %x ret i32 %sel } define i32 @select_icmp_trunc_8_ne_0_or_128_alt(i32 %x) { ; CHECK-LABEL: @select_icmp_trunc_8_ne_0_or_128_alt( ; CHECK-NEXT: [[OR:%.*]] = or i32 [[X:%.*]], 128 ; CHECK-NEXT: ret i32 [[OR]] ; %trunc = trunc i32 %x to i8 %cmp = icmp slt i8 %trunc, 0 %or = or i32 %x, 128 %sel = select i1 %cmp, i32 %x, i32 %or ret i32 %sel } define i32 @select_icmp_trunc_8_eq_0_or_128(i32 %x) { ; CHECK-LABEL: @select_icmp_trunc_8_eq_0_or_128( ; CHECK-NEXT: ret i32 [[X:%.*]] ; %trunc = trunc i32 %x to i8 %cmp = icmp slt i8 %trunc, 0 %or = or i32 %x, 128 %sel = select i1 %cmp, i32 %or, i32 %x ret i32 %sel } define i32 @select_icmp_trunc_8_eq_0_or_128_alt(i32 %x) { ; CHECK-LABEL: @select_icmp_trunc_8_eq_0_or_128_alt( ; CHECK-NEXT: ret i32 [[X:%.*]] ; %trunc = trunc i32 %x to i8 %cmp = icmp sgt i8 %trunc, -1 %or = or i32 %x, 128 %sel = select i1 %cmp, i32 %x, i32 %or ret i32 %sel } define i32 @select_icmp_trunc_8_eq_0_and_not_8(i32 %x) { ; CHECK-LABEL: @select_icmp_trunc_8_eq_0_and_not_8( ; CHECK-NEXT: [[AND:%.*]] = and i32 [[X:%.*]], -9 ; CHECK-NEXT: ret i32 [[AND]] ; %trunc = trunc i32 %x to i4 %cmp = icmp sgt i4 %trunc, -1 %and = and i32 %x, -9 %sel = select i1 %cmp, i32 %x, i32 %and ret i32 %sel } define i32 @select_icmp_trunc_8_eq_0_and_not_8_alt(i32 %x) { ; CHECK-LABEL: @select_icmp_trunc_8_eq_0_and_not_8_alt( ; CHECK-NEXT: [[AND:%.*]] = and i32 [[X:%.*]], -9 ; CHECK-NEXT: ret i32 [[AND]] ; %trunc = trunc i32 %x to i4 %cmp = icmp slt i4 %trunc, 0 %and = and i32 %x, -9 %sel = select i1 %cmp, i32 %and, i32 %x ret i32 %sel } define i32 @select_icmp_trunc_8_ne_0_and_not_8(i32 %x) { ; CHECK-LABEL: @select_icmp_trunc_8_ne_0_and_not_8( ; CHECK-NEXT: ret i32 [[X:%.*]] ; %trunc = trunc i32 %x to i4 %cmp = icmp slt i4 %trunc, 0 %and = and i32 %x, -9 %sel = select i1 %cmp, i32 %x, i32 %and ret i32 %sel } define i32 @select_icmp_trunc_8_ne_0_and_not_8_alt(i32 %x) { ; CHECK-LABEL: @select_icmp_trunc_8_ne_0_and_not_8_alt( ; CHECK-NEXT: ret i32 [[X:%.*]] ; %trunc = trunc i32 %x to i4 %cmp = icmp sgt i4 %trunc, -1 %and = and i32 %x, -9 %sel = select i1 %cmp, i32 %and, i32 %x ret i32 %sel } ; Make sure that at least a few of the same patterns are repeated with vector types. define <2 x i32> @select_icmp_and_8_ne_0_and_not_8_vec(<2 x i32> %x) { ; CHECK-LABEL: @select_icmp_and_8_ne_0_and_not_8_vec( ; CHECK-NEXT: ret <2 x i32> [[X:%.*]] ; %and = and <2 x i32> %x, <i32 8, i32 8> %cmp = icmp ne <2 x i32> %and, zeroinitializer %and1 = and <2 x i32> %x, <i32 -9, i32 -9> %sel = select <2 x i1> %cmp, <2 x i32> %x, <2 x i32> %and1 ret <2 x i32> %sel } define <2 x i32> @select_icmp_trunc_8_ne_0_and_not_8_alt_vec(<2 x i32> %x) { ; CHECK-LABEL: @select_icmp_trunc_8_ne_0_and_not_8_alt_vec( ; CHECK-NEXT: ret <2 x i32> [[X:%.*]] ; %trunc = trunc <2 x i32> %x to <2 x i4> %cmp = icmp sgt <2 x i4> %trunc, <i4 -1, i4 -1> %and = and <2 x i32> %x, <i32 -9, i32 -9> %sel = select <2 x i1> %cmp, <2 x i32> %and, <2 x i32> %x ret <2 x i32> %sel } ; Insert a bit from x into y? This should be possible in InstCombine, but not InstSimplify? define i32 @select_icmp_x_and_8_eq_0_y_and_not_8(i32 %x, i32 %y) { ; CHECK-LABEL: @select_icmp_x_and_8_eq_0_y_and_not_8( ; CHECK-NEXT: [[AND:%.*]] = and i32 [[X:%.*]], 8 ; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[AND]], 0 ; CHECK-NEXT: [[AND1:%.*]] = and i32 [[Y:%.*]], -9 ; CHECK-NEXT: [[Y_AND1:%.*]] = select i1 [[CMP]], i32 [[Y]], i32 [[AND1]] ; CHECK-NEXT: ret i32 [[Y_AND1]] ; %and = and i32 %x, 8 %cmp = icmp eq i32 %and, 0 %and1 = and i32 %y, -9 %y.and1 = select i1 %cmp, i32 %y, i32 %and1 ret i32 %y.and1 } define i64 @select_icmp_x_and_8_eq_0_y64_and_not_8(i32 %x, i64 %y) { ; CHECK-LABEL: @select_icmp_x_and_8_eq_0_y64_and_not_8( ; CHECK-NEXT: [[AND:%.*]] = and i32 [[X:%.*]], 8 ; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[AND]], 0 ; CHECK-NEXT: [[AND1:%.*]] = and i64 [[Y:%.*]], -9 ; CHECK-NEXT: [[Y_AND1:%.*]] = select i1 [[CMP]], i64 [[Y]], i64 [[AND1]] ; CHECK-NEXT: ret i64 [[Y_AND1]] ; %and = and i32 %x, 8 %cmp = icmp eq i32 %and, 0 %and1 = and i64 %y, -9 %y.and1 = select i1 %cmp, i64 %y, i64 %and1 ret i64 %y.and1 } define i64 @select_icmp_x_and_8_ne_0_y64_and_not_8(i32 %x, i64 %y) { ; CHECK-LABEL: @select_icmp_x_and_8_ne_0_y64_and_not_8( ; CHECK-NEXT: [[AND:%.*]] = and i32 [[X:%.*]], 8 ; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[AND]], 0 ; CHECK-NEXT: [[AND1:%.*]] = and i64 [[Y:%.*]], -9 ; CHECK-NEXT: [[AND1_Y:%.*]] = select i1 [[CMP]], i64 [[AND1]], i64 [[Y]] ; CHECK-NEXT: ret i64 [[AND1_Y]] ; %and = and i32 %x, 8 %cmp = icmp eq i32 %and, 0 %and1 = and i64 %y, -9 %and1.y = select i1 %cmp, i64 %and1, i64 %y ret i64 %and1.y } ; Don't crash on a pointer or aggregate type. define i32* @select_icmp_pointers(i32* %x, i32* %y) { ; CHECK-LABEL: @select_icmp_pointers( ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32* [[X:%.*]], null ; CHECK-NEXT: [[SEL:%.*]] = select i1 [[CMP]], i32* [[X]], i32* [[Y:%.*]] ; CHECK-NEXT: ret i32* [[SEL]] ; %cmp = icmp slt i32* %x, null %sel = select i1 %cmp, i32* %x, i32* %y ret i32* %sel } ; If the condition is known, we don't need to select, but we're not ; doing this fold here to avoid compile-time cost. declare void @llvm.assume(i1) define i8 @assume_sel_cond(i1 %cond, i8 %x, i8 %y) { ; CHECK-LABEL: @assume_sel_cond( ; CHECK-NEXT: call void @llvm.assume(i1 [[COND:%.*]]) ; CHECK-NEXT: [[SEL:%.*]] = select i1 [[COND]], i8 [[X:%.*]], i8 [[Y:%.*]] ; CHECK-NEXT: ret i8 [[SEL]] ; call void @llvm.assume(i1 %cond) %sel = select i1 %cond, i8 %x, i8 %y ret i8 %sel } define i8 @do_not_assume_sel_cond(i1 %cond, i8 %x, i8 %y) { ; CHECK-LABEL: @do_not_assume_sel_cond( ; CHECK-NEXT: [[NOTCOND:%.*]] = icmp eq i1 [[COND:%.*]], false ; CHECK-NEXT: call void @llvm.assume(i1 [[NOTCOND]]) ; CHECK-NEXT: [[SEL:%.*]] = select i1 [[COND]], i8 [[X:%.*]], i8 [[Y:%.*]] ; CHECK-NEXT: ret i8 [[SEL]] ; %notcond = icmp eq i1 %cond, false call void @llvm.assume(i1 %notcond) %sel = select i1 %cond, i8 %x, i8 %y ret i8 %sel } define i32* @select_icmp_eq_0_gep_operand(i32* %base, i64 %n) { ; CHECK-LABEL: @select_icmp_eq_0_gep_operand( ; CHECK-NEXT: [[GEP:%.*]] = getelementptr i32, i32* [[BASE:%.*]], i64 [[N:%.*]] ; CHECK-NEXT: ret i32* [[GEP]] ; %cond = icmp eq i64 %n, 0 %gep = getelementptr i32, i32* %base, i64 %n %r = select i1 %cond, i32* %base, i32* %gep ret i32* %r } define i32* @select_icmp_ne_0_gep_operand(i32* %base, i64 %n) { ; CHECK-LABEL: @select_icmp_ne_0_gep_operand( ; CHECK-NEXT: [[GEP:%.*]] = getelementptr i32, i32* [[BASE:%.*]], i64 [[N:%.*]] ; CHECK-NEXT: ret i32* [[GEP]] ; %cond = icmp ne i64 %n, 0 %gep = getelementptr i32, i32* %base, i64 %n %r = select i1 %cond, i32* %gep, i32* %base ret i32* %r }