[PATCH] D55642: [X86] Fix assert fails in pass X86AvoidSFBPass

[Pengfei Wang via Phabricator via llvm-commits]

pengfei created this revision.
pengfei added reviewers: craig.topper, smaslov, LuoYuanke, lsaba, manojgupta.
Herald added a subscriber: llvm-commits.

The function removeRedundantBlockingStores is supposed to remove any blocking stores contained in each other in lockingStoresDispSizeMap.
But it currently looks only at the previous one, which will miss some cases that result in assert.

This patch refine the function to check all previous layouts until find the uncontained one. So all redundant stores will be removed.


Repository:
  rL LLVM

https://reviews.llvm.org/D55642

Files:
  lib/Target/X86/X86AvoidStoreForwardingBlocks.cpp
  test/CodeGen/X86/pr38743.ll


Index: test/CodeGen/X86/pr38743.ll
===================================================================
--- /dev/null
+++ test/CodeGen/X86/pr38743.ll
@@ -0,0 +1,57 @@
+; RUN: llc < %s
+
+%0 = type { %1 }
+%1 = type { %2 }
+%2 = type { %3 }
+%3 = type { %4 }
+%4 = type { %5 }
+%5 = type { i64, i64, i8* }
+%6 = type { %7, [23 x i8] }
+%7 = type { i8 }
+
+ at .str.16 = external dso_local unnamed_addr constant [16 x i8], align 1
+ at .str.17 = external dso_local unnamed_addr constant [12 x i8], align 1
+ at .str.18 = external dso_local unnamed_addr constant [15 x i8], align 1
+
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture writeonly, i8* nocapture readonly, i64, i1) #0
+
+define void @pr38743() #1 align 2 {
+bb:
+  %tmp = alloca %0, align 16
+  %tmp1 = bitcast %0* %tmp to i8*
+  switch i32 undef, label %bb11 [
+    i32 1, label %bb2
+    i32 4, label %bb5
+    i32 2, label %bb5
+    i32 3, label %bb8
+  ]
+
+bb2:                                              ; preds = %bb
+  %tmp3 = bitcast %0* %tmp to %6*
+  %tmp4 = getelementptr inbounds %6, %6* %tmp3, i64 0, i32 1, i64 0
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull align 1 %tmp4, i8* align 1 getelementptr inbounds ([16 x i8], [16 x i8]* @.str.16, i64 0, i64 0), i64 15, i1 false)
+  br label %bb12
+
+bb5:                                              ; preds = %bb, %bb
+  %tmp6 = bitcast %0* %tmp to %6*
+  %tmp7 = getelementptr inbounds %6, %6* %tmp6, i64 0, i32 1, i64 0
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull align 1 %tmp7, i8* align 1 getelementptr inbounds ([12 x i8], [12 x i8]* @.str.17, i64 0, i64 0), i64 11, i1 false)
+  br label %bb12
+
+bb8:                                              ; preds = %bb
+  %tmp9 = bitcast %0* %tmp to %6*
+  %tmp10 = getelementptr inbounds %6, %6* %tmp9, i64 0, i32 1, i64 0
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull align 1 %tmp10, i8* align 1 getelementptr inbounds ([15 x i8], [15 x i8]* @.str.18, i64 0, i64 0), i64 14, i1 false)
+  br label %bb12
+
+bb11:                                             ; preds = %bb
+  unreachable
+
+bb12:                                             ; preds = %bb8, %bb5, %bb2
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull align 8 undef, i8* nonnull align 16 %tmp1, i64 24, i1 false) #2
+  ret void
+}
+
+attributes #0 = { argmemonly nounwind }
+attributes #1 = { "target-features"="+sse,+sse2,+sse3,+sse4.2" }
+attributes #2 = { nounwind }
Index: lib/Target/X86/X86AvoidStoreForwardingBlocks.cpp
===================================================================
--- lib/Target/X86/X86AvoidStoreForwardingBlocks.cpp
+++ lib/Target/X86/X86AvoidStoreForwardingBlocks.cpp
@@ -641,21 +641,23 @@
   if (BlockingStoresDispSizeMap.size() <= 1)
     return;
 
-  int64_t PrevDisp = BlockingStoresDispSizeMap.begin()->first;
-  unsigned PrevSize = BlockingStoresDispSizeMap.begin()->second;
-  SmallVector<int64_t, 2> ForRemoval;
-  for (auto DispSizePair = std::next(BlockingStoresDispSizeMap.begin());
+  SmallVector<std::pair<const int64_t, unsigned>, 0> DispSizeStack;
+  for (auto DispSizePair = BlockingStoresDispSizeMap.begin();
        DispSizePair != BlockingStoresDispSizeMap.end(); ++DispSizePair) {
     int64_t CurrDisp = DispSizePair->first;
     unsigned CurrSize = DispSizePair->second;
-    if (CurrDisp + CurrSize <= PrevDisp + PrevSize) {
-      ForRemoval.push_back(PrevDisp);
+    while (DispSizeStack.size()) {
+      int64_t PrevDisp = DispSizeStack.back().first;
+      unsigned PrevSize = DispSizeStack.back().second;
+      if (CurrDisp + CurrSize > PrevDisp + PrevSize)
+        break;
+      DispSizeStack.pop_back();
     }
-    PrevDisp = CurrDisp;
-    PrevSize = CurrSize;
+    DispSizeStack.push_back(*DispSizePair);
   }
-  for (auto Disp : ForRemoval)
-    BlockingStoresDispSizeMap.erase(Disp);
+  BlockingStoresDispSizeMap.clear();
+  for (auto Disp : DispSizeStack)
+    BlockingStoresDispSizeMap.insert(Disp);
 }
 
 bool X86AvoidSFBPass::runOnMachineFunction(MachineFunction &MF) {


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D55642.177997.patch
Type: text/x-patch
Size: 3997 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20181213/9873f76a/attachment.bin>