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author | Owen Anderson <resistor@mac.com> | 2010-08-19 22:15:40 +0000 |
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committer | Owen Anderson <resistor@mac.com> | 2010-08-19 22:15:40 +0000 |
commit | 9419cab4c360d532bb5c3e171cdc8eca400b1b53 (patch) | |
tree | 4e9728bae3746d75963493388c7176a7f80a6273 /test/Transforms | |
parent | b57326c8aab6f6089b29e324c39811d494d6fc42 (diff) | |
download | external_llvm-9419cab4c360d532bb5c3e171cdc8eca400b1b53.zip external_llvm-9419cab4c360d532bb5c3e171cdc8eca400b1b53.tar.gz external_llvm-9419cab4c360d532bb5c3e171cdc8eca400b1b53.tar.bz2 |
When a set of bitmask operations, typically from a bitfield initialization, only modifies the low bytes of a value,
we can narrow the store to only over-write the affected bytes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111568 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test/Transforms')
-rw-r--r-- | test/Transforms/InstCombine/2010-08-19-StoreNarrowing.ll | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/test/Transforms/InstCombine/2010-08-19-StoreNarrowing.ll b/test/Transforms/InstCombine/2010-08-19-StoreNarrowing.ll new file mode 100644 index 0000000..d4d5289 --- /dev/null +++ b/test/Transforms/InstCombine/2010-08-19-StoreNarrowing.ll @@ -0,0 +1,21 @@ +; RUN: opt -S -instcombine %s | not grep and +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" +target triple = "x86_64-apple-darwin10.0.0" + +%class.A = type { i8, [3 x i8] } + +define void @_ZN1AC2Ev(%class.A* %this) nounwind ssp align 2 { +entry: + %0 = bitcast %class.A* %this to i32* ; <i32*> [#uses=5] + %1 = load i32* %0, align 4 ; <i32> [#uses=1] + %2 = and i32 %1, -8 ; <i32> [#uses=2] + store i32 %2, i32* %0, align 4 + %3 = and i32 %2, -57 ; <i32> [#uses=1] + %4 = or i32 %3, 8 ; <i32> [#uses=2] + store i32 %4, i32* %0, align 4 + %5 = and i32 %4, -65 ; <i32> [#uses=2] + store i32 %5, i32* %0, align 4 + %6 = and i32 %5, -129 ; <i32> [#uses=1] + store i32 %6, i32* %0, align 4 + ret void +} |