diff options
Diffstat (limited to 'llvm/test/Transforms/InstCombine/memcmp-constant-fold.ll')
| -rw-r--r-- | llvm/test/Transforms/InstCombine/memcmp-constant-fold.ll | 49 |
1 files changed, 39 insertions, 10 deletions
diff --git a/llvm/test/Transforms/InstCombine/memcmp-constant-fold.ll b/llvm/test/Transforms/InstCombine/memcmp-constant-fold.ll index b19f17c818d..211b3b5ab2c 100644 --- a/llvm/test/Transforms/InstCombine/memcmp-constant-fold.ll +++ b/llvm/test/Transforms/InstCombine/memcmp-constant-fold.ll @@ -3,31 +3,45 @@ declare i32 @memcmp(i8*, i8*, i64) -; TODO: The alignment of this constant does not matter. We constant fold the load. +; 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(i8* align 4 %x) { -; ALL-LABEL: @memcmp_4bytes_unaligned_constant_i8( -; ALL-NEXT: [[CALL:%.*]] = tail call i32 @memcmp(i8* %x, i8* getelementptr inbounds ([4 x i8], [4 x i8]* @charbuf, i64 0, i64 0), i64 4) -; ALL-NEXT: [[CMPEQ0:%.*]] = icmp eq i32 [[CALL]], 0 -; ALL-NEXT: ret i1 [[CMPEQ0]] +; LE-LABEL: @memcmp_4bytes_unaligned_constant_i8( +; LE-NEXT: [[TMP1:%.*]] = bitcast i8* %x to i32* +; LE-NEXT: [[LHSV:%.*]] = load i32, i32* [[TMP1]], align 4 +; LE-NEXT: [[TMP2:%.*]] = icmp eq i32 [[LHSV]], 16777216 +; LE-NEXT: ret i1 [[TMP2]] +; +; BE-LABEL: @memcmp_4bytes_unaligned_constant_i8( +; BE-NEXT: [[TMP1:%.*]] = bitcast i8* %x to i32* +; BE-NEXT: [[LHSV:%.*]] = load i32, i32* [[TMP1]], align 4 +; BE-NEXT: [[TMP2:%.*]] = icmp eq i32 [[LHSV]], 1 +; BE-NEXT: ret i1 [[TMP2]] ; %call = tail call i32 @memcmp(i8* %x, i8* getelementptr inbounds ([4 x i8], [4 x i8]* @charbuf, i64 0, i64 0), i64 4) %cmpeq0 = icmp eq i32 %call, 0 ret i1 %cmpeq0 } -; TODO: We still don't care about alignment of the constant. We are not limited to constant folding only i8 arrays. +; 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(i8* align 4 %x) { -; ALL-LABEL: @memcmp_4bytes_unaligned_constant_i16( -; ALL-NEXT: [[CALL:%.*]] = tail call i32 @memcmp(i8* bitcast ([4 x i16]* @intbuf_unaligned to i8*), i8* %x, i64 4) -; ALL-NEXT: [[CMPEQ0:%.*]] = icmp eq i32 [[CALL]], 0 -; ALL-NEXT: ret i1 [[CMPEQ0]] +; LE-LABEL: @memcmp_4bytes_unaligned_constant_i16( +; LE-NEXT: [[TMP1:%.*]] = bitcast i8* %x to i32* +; LE-NEXT: [[RHSV:%.*]] = load i32, i32* [[TMP1]], align 4 +; LE-NEXT: [[TMP2:%.*]] = icmp eq i32 [[RHSV]], 131073 +; LE-NEXT: ret i1 [[TMP2]] +; +; BE-LABEL: @memcmp_4bytes_unaligned_constant_i16( +; BE-NEXT: [[TMP1:%.*]] = bitcast i8* %x to i32* +; BE-NEXT: [[RHSV:%.*]] = load i32, i32* [[TMP1]], align 4 +; BE-NEXT: [[TMP2:%.*]] = icmp eq i32 [[RHSV]], 65538 +; BE-NEXT: ret i1 [[TMP2]] ; %call = tail call i32 @memcmp(i8* bitcast (i16* getelementptr inbounds ([4 x i16], [4 x i16]* @intbuf_unaligned, i64 0, i64 0) to i8*), i8* %x, i64 4) %cmpeq0 = icmp eq i32 %call, 0 @@ -49,3 +63,18 @@ define i1 @memcmp_3bytes_aligned_constant_i32(i8* align 4 %x) { ret i1 %cmpeq0 } +; A sloppy implementation would infinite loop by recreating the unused instructions. + +define i1 @memcmp_4bytes_one_unaligned_i8(i8* align 4 %x, i8* align 1 %y) { +; ALL-LABEL: @memcmp_4bytes_one_unaligned_i8( +; ALL-NEXT: [[CALL:%.*]] = tail call i32 @memcmp(i8* %x, i8* %y, i64 4) +; ALL-NEXT: [[CMPEQ0:%.*]] = icmp eq i32 [[CALL]], 0 +; ALL-NEXT: ret i1 [[CMPEQ0]] +; + %bc = bitcast i8* %x to i32* + %lhsv = load i32, i32* %bc + %call = tail call i32 @memcmp(i8* %x, i8* %y, i64 4) + %cmpeq0 = icmp eq i32 %call, 0 + ret i1 %cmpeq0 +} + |
