[llvm] 344a3d0 - [MemorySSA] Rename uses in blocks with Phis.
Alina Sbirlea via llvm-commits
llvm-commits at lists.llvm.org
Wed Sep 16 17:27:24 PDT 2020
Author: Alina Sbirlea
Date: 2020-09-16T17:24:17-07:00
New Revision: 344a3d0bc0fb0868b519c3342b4982d6121eece3
URL: https://github.com/llvm/llvm-project/commit/344a3d0bc0fb0868b519c3342b4982d6121eece3
DIFF: https://github.com/llvm/llvm-project/commit/344a3d0bc0fb0868b519c3342b4982d6121eece3.diff
LOG: [MemorySSA] Rename uses in blocks with Phis.
Renaming should include blocks with existing Phis.
Resolves PR45927.
Differential Revision: https://reviews.llvm.org/D87661
Added:
llvm/test/Analysis/MemorySSA/pr45927.ll
Modified:
llvm/lib/Analysis/MemorySSAUpdater.cpp
Removed:
################################################################################
diff --git a/llvm/lib/Analysis/MemorySSAUpdater.cpp b/llvm/lib/Analysis/MemorySSAUpdater.cpp
index 19f434f82cc6..f633fbe4e12b 100644
--- a/llvm/lib/Analysis/MemorySSAUpdater.cpp
+++ b/llvm/lib/Analysis/MemorySSAUpdater.cpp
@@ -342,6 +342,8 @@ void MemorySSAUpdater::insertDef(MemoryDef *MD, bool RenameUses) {
SmallVector<WeakVH, 8> FixupList(InsertedPHIs.begin(), InsertedPHIs.end());
+ SmallSet<WeakVH, 8> ExistingPhis;
+
// Remember the index where we may insert new phis.
unsigned NewPhiIndex = InsertedPHIs.size();
if (!DefBeforeSameBlock) {
@@ -382,6 +384,8 @@ void MemorySSAUpdater::insertDef(MemoryDef *MD, bool RenameUses) {
if (!MPhi) {
MPhi = MSSA->createMemoryPhi(BBIDF);
NewInsertedPHIs.push_back(MPhi);
+ } else {
+ ExistingPhis.insert(MPhi);
}
// Add the phis created into the IDF blocks to NonOptPhis, so they are not
// optimized out as trivial by the call to getPreviousDefFromEnd below.
@@ -447,6 +451,13 @@ void MemorySSAUpdater::insertDef(MemoryDef *MD, bool RenameUses) {
if (Phi)
MSSA->renamePass(Phi->getBlock(), nullptr, Visited);
}
+ // Existing Phi blocks may need renaming too, if an access was previously
+ // optimized and the inserted Defs "covers" the Optimized value.
+ for (auto &MP : ExistingPhis) {
+ MemoryPhi *Phi = dyn_cast_or_null<MemoryPhi>(MP);
+ if (Phi)
+ MSSA->renamePass(Phi->getBlock(), nullptr, Visited);
+ }
}
}
@@ -1322,6 +1333,7 @@ void MemorySSAUpdater::removeMemoryAccess(MemoryAccess *MA, bool OptimizePhis) {
// Note: We assume MemorySSA is not used in metadata since it's not really
// part of the IR.
+ assert(NewDefTarget != MA && "Going into an infinite loop");
while (!MA->use_empty()) {
Use &U = *MA->use_begin();
if (auto *MUD = dyn_cast<MemoryUseOrDef>(U.getUser()))
diff --git a/llvm/test/Analysis/MemorySSA/pr45927.ll b/llvm/test/Analysis/MemorySSA/pr45927.ll
new file mode 100644
index 000000000000..b6c1d6ba86c1
--- /dev/null
+++ b/llvm/test/Analysis/MemorySSA/pr45927.ll
@@ -0,0 +1,73 @@
+; RUN: opt -disable-output -loop-simplify -lcssa -licm -print-memoryssa < %s 2>&1 | FileCheck %s
+; RUN: opt -disable-output -aa-pipeline=basic-aa -passes='loop-mssa(licm),print<memoryssa>' < %s 2>&1 | FileCheck %s
+
+
+ at a = external dso_local global i16, align 1
+ at c = external dso_local global i16, align 1
+
+; CHECK-LABEL: @main()
+
+; CHECK: entry:
+; CHECK-NEXT: %res.addr.i = alloca i16
+; CHECK-NEXT: ; MemoryUse(liveOnEntry)
+; CHECK-NEXT: %c.promoted = load i16, i16* @c
+; CHECK-NEXT: br label %for.cond.i
+
+; CHECK: for.cond.i:
+; CHECK-NEXT: ; [[NO5:.*]] = MemoryPhi({entry,liveOnEntry},{f.exit.i,[[NO5]]})
+; CHECK-NEXT: %inc.i1 = phi i16 [ %inc.i, %f.exit.i ], [ %c.promoted, %entry ]
+; CHECK-NEXT: %inc.i = add nsw i16 %inc.i1, 1
+; CHECK-NEXT: br i1 false, label %f.exit.thread.i, label %f.exit.i
+
+; CHECK: f.exit.thread.i:
+; CHECK-NEXT: %inc.i.lcssa = phi i16 [ %inc.i, %for.cond.i ]
+; CHECK-NEXT: ; [[NO6:.*]] = MemoryDef([[NO5]])
+; CHECK-NEXT: store i16 %inc.i.lcssa, i16* @c, align 1
+; CHECK-NEXT: ; [[NO2:.*]] = MemoryDef([[NO6]])
+; CHECK-NEXT: store i16 1, i16* @a, align 1
+; CHECK-NEXT: ; MemoryUse([[NO2]])
+; CHECK-NEXT: %tmp2 = load i16, i16* @c, align 1
+; CHECK-NEXT: br label %g.exit
+
+; CHECK: f.exit.i
+; CHECK-NEXT: br i1 false, label %g.exit.loopexit, label %for.cond.i
+
+; CHECK: g.exit.loopexit:
+; CHECK-NEXT: %inc.i.lcssa2 = phi i16 [ %inc.i, %f.exit.i ]
+; CHECK-NEXT: ; [[NO7:.*]] = MemoryDef([[NO5]])
+; CHECK-NEXT: store i16 %inc.i.lcssa2, i16* @c, align 1
+; CHECK-NEXT: br label %g.exit
+
+; CHECK: g.exit
+; CHECK-NEXT: ; [[NO4:.*]] = MemoryPhi({f.exit.thread.i,[[NO2]]},{g.exit.loopexit,[[NO7]]})
+; CHECK-NEXT: ; MemoryUse([[NO4]])
+; CHECK-NEXT: %tmp1 = load i16, i16* @c, align 1
+; CHECK-NEXT: ; [[NO3:.*]] = MemoryDef([[NO4]])
+; CHECK-NEXT: store i16 %tmp1, i16* %res.addr.i, align 1
+; CHECK-NEXT: ret void
+
+define dso_local void @main() {
+entry:
+ %res.addr.i = alloca i16, align 1
+ br label %for.cond.i
+
+for.cond.i: ; preds = %f.exit.i, %entry
+ %tmp0 = load i16, i16* @c, align 1
+ %inc.i = add nsw i16 %tmp0, 1
+ store i16 %inc.i, i16* @c, align 1
+ br i1 false, label %f.exit.thread.i, label %f.exit.i
+
+f.exit.thread.i: ; preds = %for.cond.i
+ store i16 1, i16* @a, align 1
+ %tmp2 = load i16, i16* @c, align 1
+ br label %g.exit
+
+f.exit.i: ; preds = %for.cond.i
+ br i1 false, label %g.exit, label %for.cond.i
+
+g.exit: ; preds = %f.exit.i, %f.exit.thread.i
+ %tmp1 = load i16, i16* @c, align 1
+ store i16 %tmp1, i16* %res.addr.i, align 1
+ ret void
+}
+
More information about the llvm-commits
mailing list