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| author | Hal Finkel <hfinkel@anl.gov> | 2014-11-03 20:21:32 +0000 |
|---|---|---|
| committer | Hal Finkel <hfinkel@anl.gov> | 2014-11-03 20:21:32 +0000 |
| commit | 1e16fa302e2c3f68ea8187e8b782397e0b24cd0f (patch) | |
| tree | 9823bb9f7600846f641e9961cd0b8759e7d8e789 /llvm/test/Transforms | |
| parent | 1ae35b902ba0482ef80fa3f778efd719c9626b41 (diff) | |
| download | bcm5719-llvm-1e16fa302e2c3f68ea8187e8b782397e0b24cd0f.tar.gz bcm5719-llvm-1e16fa302e2c3f68ea8187e8b782397e0b24cd0f.zip | |
EarlyCSE should ignore calls to @llvm.assume
EarlyCSE uses a simple generation scheme for handling memory-based
dependencies, and calls to @llvm.assume (which are marked as writing to memory
to ensure the preservation of control dependencies) disturb that scheme
unnecessarily. Skipping calls to @llvm.assume is legal, and the alternative
(adding AA calls in EarlyCSE) is likely undesirable (we have GVN for that).
Fixes PR21448.
llvm-svn: 221175
Diffstat (limited to 'llvm/test/Transforms')
| -rw-r--r-- | llvm/test/Transforms/EarlyCSE/basic.ll | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/llvm/test/Transforms/EarlyCSE/basic.ll b/llvm/test/Transforms/EarlyCSE/basic.ll index 80704df9852..9f3e474aff9 100644 --- a/llvm/test/Transforms/EarlyCSE/basic.ll +++ b/llvm/test/Transforms/EarlyCSE/basic.ll @@ -1,5 +1,6 @@ ; RUN: opt < %s -S -early-cse | FileCheck %s +declare void @llvm.assume(i1) nounwind ; CHECK-LABEL: @test1( define void @test1(i8 %V, i32 *%P) { @@ -42,6 +43,16 @@ define i32 @test2(i32 *%P) { ; CHECK: ret i32 0 } +; CHECK-LABEL: @test2a( +define i32 @test2a(i32 *%P, i1 %b) { + %V1 = load i32* %P + tail call void @llvm.assume(i1 %b) + %V2 = load i32* %P + %Diff = sub i32 %V1, %V2 + ret i32 %Diff + ; CHECK: ret i32 0 +} + ;; Cross block load value numbering. ; CHECK-LABEL: @test3( define i32 @test3(i32 *%P, i1 %Cond) { @@ -58,6 +69,22 @@ F: ; CHECK: ret i32 0 } +; CHECK-LABEL: @test3a( +define i32 @test3a(i32 *%P, i1 %Cond, i1 %b) { + %V1 = load i32* %P + br i1 %Cond, label %T, label %F +T: + store i32 4, i32* %P + ret i32 42 +F: + tail call void @llvm.assume(i1 %b) + %V2 = load i32* %P + %Diff = sub i32 %V1, %V2 + ret i32 %Diff + ; CHECK: F: + ; CHECK: ret i32 0 +} + ;; Cross block load value numbering stops when stores happen. ; CHECK-LABEL: @test4( define i32 @test4(i32 *%P, i1 %Cond) { @@ -97,6 +124,15 @@ define i32 @test6(i32 *%P) { ; CHECK: ret i32 42 } +; CHECK-LABEL: @test6a( +define i32 @test6a(i32 *%P, i1 %b) { + store i32 42, i32* %P + tail call void @llvm.assume(i1 %b) + %V1 = load i32* %P + ret i32 %V1 + ; CHECK: ret i32 42 +} + ;; Trivial dead store elimination. ; CHECK-LABEL: @test7( define void @test7(i32 *%P) { |
