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