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Diffstat (limited to 'test/Transforms/GVN/calloc-load-removal.ll')
| -rw-r--r-- | test/Transforms/GVN/calloc-load-removal.ll | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/test/Transforms/GVN/calloc-load-removal.ll b/test/Transforms/GVN/calloc-load-removal.ll new file mode 100644 index 0000000..2dde5b7 --- /dev/null +++ b/test/Transforms/GVN/calloc-load-removal.ll @@ -0,0 +1,25 @@ +; RUN: opt -S -basicaa -gvn < %s | FileCheck %s +; RUN: opt -S -basicaa -gvn -disable-simplify-libcalls < %s | FileCheck %s -check-prefix=CHECK_NO_LIBCALLS +; Check that loads from calloc are recognized as being zero. + +target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128" + +; Function Attrs: nounwind uwtable +define i32 @test1() { + %1 = tail call noalias i8* @calloc(i64 1, i64 4) + %2 = bitcast i8* %1 to i32* + ; This load is trivially constant zero + %3 = load i32* %2, align 4 + ret i32 %3 + +; CHECK-LABEL: @test1( +; CHECK-NOT: %3 = load i32* %2, align 4 +; CHECK: ret i32 0 + +; CHECK_NO_LIBCALLS-LABEL: @test1( +; CHECK_NO_LIBCALLS: load +; CHECK_NO_LIBCALLS: ret i32 % + +} + +declare noalias i8* @calloc(i64, i64) |