diff options
| author | Alina Sbirlea <asbirlea@google.com> | 2017-12-22 19:54:03 +0000 |
|---|---|---|
| committer | Alina Sbirlea <asbirlea@google.com> | 2017-12-22 19:54:03 +0000 |
| commit | d14c0e60145904027de6001ac169ba50a8cdf6e8 (patch) | |
| tree | 9af45bc05b83636e29e94fdb3d8c8ec79ee2ca74 /test/Analysis | |
| parent | ecdc6849ca3bcc3d2c0dbf38f73a3b939637dd93 (diff) | |
[MemorySSA] Allow reordering of loads that alias in the presence of volatile loads.
Summary:
Make MemorySSA allow reordering of two loads that may alias, when one is volatile.
This makes MemorySSA less conservative and behaving the same as the AliasSetTracker.
For more context, see D16875.
LLVM language reference: "The optimizers must not change the number of volatile operations or change their order of execution relative to other volatile operations. The optimizers may change the order of volatile operations relative to non-volatile operations. This is not Java’s “volatile” and has no cross-thread synchronization behavior."
Reviewers: george.burgess.iv, dberlin
Subscribers: sanjoy, reames, hfinkel, llvm-commits, Prazek
Differential Revision: https://reviews.llvm.org/D41525
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@321382 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test/Analysis')
| -rw-r--r-- | test/Analysis/MemorySSA/volatile-clobber.ll | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/test/Analysis/MemorySSA/volatile-clobber.ll b/test/Analysis/MemorySSA/volatile-clobber.ll index d6f960f3e38..53df7de499b 100644 --- a/test/Analysis/MemorySSA/volatile-clobber.ll +++ b/test/Analysis/MemorySSA/volatile-clobber.ll @@ -22,8 +22,7 @@ define i32 @foo() { ret i32 %4 } -; Ensuring that we don't automatically hoist nonvolatile loads around volatile -; loads +; Ensuring we allow hoisting nonvolatile loads around volatile loads. ; CHECK-LABEL define void @volatile_only define void @volatile_only(i32* %arg1, i32* %arg2) { ; Trivially NoAlias/MustAlias @@ -36,7 +35,7 @@ define void @volatile_only(i32* %arg1, i32* %arg2) { ; CHECK: MemoryUse(liveOnEntry) ; CHECK-NEXT: load i32, i32* %b load i32, i32* %b -; CHECK: MemoryUse(1) +; CHECK: MemoryUse(liveOnEntry) ; CHECK-NEXT: load i32, i32* %a load i32, i32* %a @@ -44,7 +43,7 @@ define void @volatile_only(i32* %arg1, i32* %arg2) { ; CHECK: 2 = MemoryDef(1) ; CHECK-NEXT: load volatile i32, i32* %arg1 load volatile i32, i32* %arg1 -; CHECK: MemoryUse(2) +; CHECK: MemoryUse(liveOnEntry) ; CHECK-NEXT: load i32, i32* %arg2 load i32, i32* %arg2 @@ -75,10 +74,10 @@ define void @volatile_atomics(i32* %arg1, i32* %arg2) { ; CHECK: MemoryUse(1) ; CHECK-NEXT: load atomic i32, i32* %b unordered, align 4 load atomic i32, i32* %b unordered, align 4 -; CHECK: MemoryUse(2) +; CHECK: MemoryUse(1) ; CHECK-NEXT: load atomic i32, i32* %a unordered, align 4 load atomic i32, i32* %a unordered, align 4 -; CHECK: MemoryUse(2) +; CHECK: MemoryUse(1) ; CHECK-NEXT: load i32, i32* %a load i32, i32* %a @@ -86,7 +85,7 @@ define void @volatile_atomics(i32* %arg1, i32* %arg2) { ; CHECK: 3 = MemoryDef(2) ; CHECK-NEXT: load atomic volatile i32, i32* %arg1 monotonic, align 4 load atomic volatile i32, i32* %arg1 monotonic, align 4 -; CHECK: MemoryUse(3) +; CHECK: MemoryUse(1) ; CHECK-NEXT: load i32, i32* %arg2 load i32, i32* %arg2 |