; NOTE: Assertions have been autogenerated by utils/update_test_checks.py ; RUN: opt < %s -passes=instcombine -S -data-layout=e-n32 | FileCheck %s --check-prefix=ALL --check-prefix=LE ; RUN: opt < %s -passes=instcombine -S -data-layout=E-n32 | FileCheck %s --check-prefix=ALL --check-prefix=BE declare i32 @memcmp(ptr, ptr, i64) ; The alignment of this constant does not matter. We constant fold the load. @charbuf = private unnamed_addr constant [4 x i8] [i8 0, i8 0, i8 0, i8 1], align 1 define i1 @memcmp_4bytes_unaligned_constant_i8(ptr align 4 %x) { ; LE-LABEL: @memcmp_4bytes_unaligned_constant_i8( ; LE-NEXT: [[LHSV:%.*]] = load i32, ptr [[X:%.*]], align 4 ; LE-NEXT: [[DOTNOT:%.*]] = icmp eq i32 [[LHSV]], 16777216 ; LE-NEXT: ret i1 [[DOTNOT]] ; ; BE-LABEL: @memcmp_4bytes_unaligned_constant_i8( ; BE-NEXT: [[LHSV:%.*]] = load i32, ptr [[X:%.*]], align 4 ; BE-NEXT: [[DOTNOT:%.*]] = icmp eq i32 [[LHSV]], 1 ; BE-NEXT: ret i1 [[DOTNOT]] ; %call = tail call i32 @memcmp(ptr %x, ptr @charbuf, i64 4) %cmpeq0 = icmp eq i32 %call, 0 ret i1 %cmpeq0 } ; We still don't care about alignment of the constant. We are not limited to constant folding only i8 arrays. ; It doesn't matter if the constant operand is the first operand to the memcmp. @intbuf_unaligned = private unnamed_addr constant [4 x i16] [i16 1, i16 2, i16 3, i16 4], align 1 define i1 @memcmp_4bytes_unaligned_constant_i16(ptr align 4 %x) { ; LE-LABEL: @memcmp_4bytes_unaligned_constant_i16( ; LE-NEXT: [[RHSV:%.*]] = load i32, ptr [[X:%.*]], align 4 ; LE-NEXT: [[DOTNOT:%.*]] = icmp eq i32 [[RHSV]], 131073 ; LE-NEXT: ret i1 [[DOTNOT]] ; ; BE-LABEL: @memcmp_4bytes_unaligned_constant_i16( ; BE-NEXT: [[RHSV:%.*]] = load i32, ptr [[X:%.*]], align 4 ; BE-NEXT: [[DOTNOT:%.*]] = icmp eq i32 [[RHSV]], 65538 ; BE-NEXT: ret i1 [[DOTNOT]] ; %call = tail call i32 @memcmp(ptr @intbuf_unaligned, ptr %x, i64 4) %cmpeq0 = icmp eq i32 %call, 0 ret i1 %cmpeq0 } ; Verif that a memcmp call where all arguments are constants is constant ; folded even for arrays of other types than i8. @intbuf = private unnamed_addr constant [2 x i32] [i32 0, i32 1], align 4 define i1 @memcmp_3bytes_aligned_constant_i32(ptr align 4 %x) { ; LE-LABEL: @memcmp_3bytes_aligned_constant_i32( ; LE-NEXT: ret i1 false ; ; BE-LABEL: @memcmp_3bytes_aligned_constant_i32( ; BE-NEXT: ret i1 true ; %call = tail call i32 @memcmp(ptr getelementptr inbounds ([2 x i32], ptr @intbuf, i64 0, i64 1), ptr @intbuf, i64 3) %cmpeq0 = icmp eq i32 %call, 0 ret i1 %cmpeq0 } ; A sloppy implementation would infinite loop by recreating the unused instructions. define i1 @memcmp_4bytes_one_unaligned_i8(ptr align 4 %x, ptr align 1 %y) { ; ALL-LABEL: @memcmp_4bytes_one_unaligned_i8( ; ALL-NEXT: [[CALL:%.*]] = tail call i32 @memcmp(ptr noundef nonnull dereferenceable(4) [[X:%.*]], ptr noundef nonnull dereferenceable(4) [[Y:%.*]], i64 4) ; ALL-NEXT: [[CMPEQ0:%.*]] = icmp eq i32 [[CALL]], 0 ; ALL-NEXT: ret i1 [[CMPEQ0]] ; %lhsv = load i32, ptr %x %call = tail call i32 @memcmp(ptr %x, ptr %y, i64 4) %cmpeq0 = icmp eq i32 %call, 0 ret i1 %cmpeq0 }