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| author | George Burgess IV <george.burgess.iv@gmail.com> | 2018-08-10 05:14:43 +0000 |
|---|---|---|
| committer | George Burgess IV <george.burgess.iv@gmail.com> | 2018-08-10 05:14:43 +0000 |
| commit | ff08c80efcd5f69b9ac9881699b45fb8aa10f15e (patch) | |
| tree | 8994606ea6ce9320ea9aab94e2039ba82ef933f1 /llvm/test/Transforms/EarlyCSE | |
| parent | 909889b2cbd55fbc4a5bb7f155bd286a82da1fef (diff) | |
| download | bcm5719-llvm-ff08c80efcd5f69b9ac9881699b45fb8aa10f15e.tar.gz bcm5719-llvm-ff08c80efcd5f69b9ac9881699b45fb8aa10f15e.zip | |
[MemorySSA] "Fix" lifetime intrinsic handling
MemorySSA currently creates MemoryAccesses for lifetime intrinsics, and
sometimes treats them as clobbers. This may/may not be the best way
forward, but while we're doing it, we should consider
MayAlias/PartialAlias to be clobbers.
The ideal fix here is probably to remove all of this reasoning about
lifetimes from MemorySSA + put it into the passes that need to care. But
that's a wayyy broader fix that needs some consensus, and we have
miscompiles + a release branch today, and this should solve the
miscompiles just as well.
differential revision is D43269. Landing without an explicit LGTM (and
without using the special please-autoclose-this syntax) so we can still
use that revision as a place to decide what the right fix here is.
llvm-svn: 339411
Diffstat (limited to 'llvm/test/Transforms/EarlyCSE')
| -rw-r--r-- | llvm/test/Transforms/EarlyCSE/memoryssa.ll | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/llvm/test/Transforms/EarlyCSE/memoryssa.ll b/llvm/test/Transforms/EarlyCSE/memoryssa.ll index 1c10efe2293..41e8d488ab4 100644 --- a/llvm/test/Transforms/EarlyCSE/memoryssa.ll +++ b/llvm/test/Transforms/EarlyCSE/memoryssa.ll @@ -106,3 +106,45 @@ end: store i32 %v2, i32* @G3 ret void } + +;; Check that we respect lifetime.start/lifetime.end intrinsics when deleting +;; stores that, without the lifetime calls, would be writebacks. +; CHECK-LABEL: @test_writeback_lifetimes( +; CHECK-NOMEMSSA-LABEL: @test_writeback_lifetimes( +define void @test_writeback_lifetimes(i32* %p) { +entry: + %q = getelementptr i32, i32* %p, i64 1 + %pv = load i32, i32* %p + %qv = load i32, i32* %q + call void @llvm.lifetime.end.p0i8(i64 8, i32* %p) + call void @llvm.lifetime.start.p0i8(i64 8, i32* %p) + ; CHECK: store i32 %pv + ; CHECK-NOMEMSSA-LABEL: store i32 %pv + store i32 %pv, i32* %p + ; CHECK: store i32 %qv, i32* %q + ; CHECK-NOMEMSSA-LABEL: store i32 %qv, i32* %q + store i32 %qv, i32* %q + ret void +} + +;; Check that we respect lifetime.start/lifetime.end intrinsics when deleting +;; stores that, without the lifetime calls, would be writebacks. +; CHECK-LABEL: @test_writeback_lifetimes_multi_arg( +; CHECK-NOMEMSSA-LABEL: @test_writeback_lifetimes_multi_arg( +define void @test_writeback_lifetimes_multi_arg(i32* %p, i32* %q) { +entry: + %pv = load i32, i32* %p + %qv = load i32, i32* %q + call void @llvm.lifetime.end.p0i8(i64 8, i32* %p) + call void @llvm.lifetime.start.p0i8(i64 8, i32* %p) + ; CHECK: store i32 %pv + ; CHECK-NOMEMSSA-LABEL: store i32 %pv + store i32 %pv, i32* %p + ; CHECK: store i32 %qv, i32* %q + ; CHECK-NOMEMSSA-LABEL: store i32 %qv, i32* %q + store i32 %qv, i32* %q + ret void +} + +declare void @llvm.lifetime.end.p0i8(i64, i32*) +declare void @llvm.lifetime.start.p0i8(i64, i32*) |
