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| -rw-r--r-- | llvm/test/Transforms/InstCombine/memcmp-constant-fold.ll | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/llvm/test/Transforms/InstCombine/memcmp-constant-fold.ll b/llvm/test/Transforms/InstCombine/memcmp-constant-fold.ll new file mode 100644 index 00000000000..b19f17c818d --- /dev/null +++ b/llvm/test/Transforms/InstCombine/memcmp-constant-fold.ll @@ -0,0 +1,51 @@ +; RUN: opt < %s -instcombine -S -data-layout=e-n32 | FileCheck %s --check-prefix=ALL --check-prefix=LE +; RUN: opt < %s -instcombine -S -data-layout=E-n32 | FileCheck %s --check-prefix=ALL --check-prefix=BE + +declare i32 @memcmp(i8*, i8*, i64) + +; TODO: 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]] +; + %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. +; 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]] +; + %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 + ret i1 %cmpeq0 +} + +; TODO: Any memcmp where all arguments are constants should be constant folded. Currently, we only handle i8 array constants. + +@intbuf = private unnamed_addr constant [2 x i32] [i32 0, i32 1], align 4 + +define i1 @memcmp_3bytes_aligned_constant_i32(i8* align 4 %x) { +; ALL-LABEL: @memcmp_3bytes_aligned_constant_i32( +; ALL-NEXT: [[CALL:%.*]] = tail call i32 @memcmp(i8* bitcast (i32* getelementptr inbounds ([2 x i32], [2 x i32]* @intbuf, i64 0, i64 1) to i8*), i8* bitcast ([2 x i32]* @intbuf to i8*), i64 3) +; ALL-NEXT: [[CMPEQ0:%.*]] = icmp eq i32 [[CALL]], 0 +; ALL-NEXT: ret i1 [[CMPEQ0]] +; + %call = tail call i32 @memcmp(i8* bitcast (i32* getelementptr inbounds ([2 x i32], [2 x i32]* @intbuf, i64 0, i64 1) to i8*), i8* bitcast (i32* getelementptr inbounds ([2 x i32], [2 x i32]* @intbuf, i64 0, i64 0) to i8*), i64 3) + %cmpeq0 = icmp eq i32 %call, 0 + ret i1 %cmpeq0 +} + |
