[llvm] 8c61f13 - [DSE,MSSA] Delete instructions after printing it.

[Florian Hahn via llvm-commits]

Author: Florian Hahn
Date: 2020-06-15T16:01:36+01:00
New Revision: 8c61f13a0f7cb4078b3dd4481c89b48fe4a50f77

URL: https://github.com/llvm/llvm-project/commit/8c61f13a0f7cb4078b3dd4481c89b48fe4a50f77
DIFF: https://github.com/llvm/llvm-project/commit/8c61f13a0f7cb4078b3dd4481c89b48fe4a50f77.diff

LOG: [DSE,MSSA] Delete instructions after printing it.

Also enables a now-passing test case, that exposed a crash caused by the
wrong order.

Added: 
    

Modified: 
    llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
    llvm/test/Transforms/DeadStoreElimination/MSSA/atomic-todo.ll
    llvm/test/Transforms/DeadStoreElimination/MSSA/atomic.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp b/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
index 45b7814b8f9b..2b77d0615bbe 100644
--- a/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
@@ -1945,9 +1945,9 @@ bool eliminateDeadStoresMemorySSA(Function &F, AliasAnalysis &AA,
     // Check if we're storing a value that we just loaded.
     if (auto *Load = dyn_cast<LoadInst>(SI->getOperand(0))) {
       if (storeIsNoop(MSSA, Load, KillingDef)) {
-        State.deleteDeadInstruction(SI);
         LLVM_DEBUG(dbgs() << "DSE: Remove Dead Store:\n  DEAD: " << *SI
                           << '\n');
+        State.deleteDeadInstruction(SI);
         NumNoopStores++;
         MadeChange = true;
         continue;

diff  --git a/llvm/test/Transforms/DeadStoreElimination/MSSA/atomic-todo.ll b/llvm/test/Transforms/DeadStoreElimination/MSSA/atomic-todo.ll
index 2a1fbde23958..d27ac812fc20 100644
--- a/llvm/test/Transforms/DeadStoreElimination/MSSA/atomic-todo.ll
+++ b/llvm/test/Transforms/DeadStoreElimination/MSSA/atomic-todo.ll
@@ -11,16 +11,6 @@ target triple = "x86_64-apple-macosx10.7.0"
 @x = common global i32 0, align 4
 @y = common global i32 0, align 4
 
-; DSE no-op unordered atomic store (allowed)
-define void @test6() {
-; CHECK-LABEL: test6
-; CHECK-NOT: store
-; CHECK: ret void
-  %x = load atomic i32, i32* @x unordered, align 4
-  store atomic i32 %x, i32* @x unordered, align 4
-  ret void
-}
-
 ; DSE across monotonic load (allowed as long as the eliminated store isUnordered)
 define i32 @test9() {
 ; CHECK-LABEL: test9

diff  --git a/llvm/test/Transforms/DeadStoreElimination/MSSA/atomic.ll b/llvm/test/Transforms/DeadStoreElimination/MSSA/atomic.ll
index 8a4515388f2d..73f6dd3e188b 100644
--- a/llvm/test/Transforms/DeadStoreElimination/MSSA/atomic.ll
+++ b/llvm/test/Transforms/DeadStoreElimination/MSSA/atomic.ll
@@ -42,6 +42,16 @@ define void @test5() {
   ret void
 }
 
+; DSE no-op unordered atomic store (allowed)
+define void @test6() {
+; CHECK-LABEL: test6
+; CHECK-NOT: store
+; CHECK: ret void
+  %x = load atomic i32, i32* @x unordered, align 4
+  store atomic i32 %x, i32* @x unordered, align 4
+  ret void
+}
+
 ; DSE seq_cst store (be conservative; DSE doesn't have infrastructure
 ; to reason about atomic operations).
 define void @test7() {