[PATCH] D70430: CodeGenPrepare: Clear maps containing AssertingVH's before deleting instructions (PR43269)

[Hans Wennborg via Phabricator via llvm-commits]

hans created this revision.
hans added reviewers: eli.friedman, haicheng.
Herald added a subscriber: hiraditya.
Herald added a project: LLVM.

This is a crude, but I think effective, fix to PR43269. Please take a look!


https://reviews.llvm.org/D70430

Files:
  llvm/lib/CodeGen/CodeGenPrepare.cpp
  llvm/test/Transforms/CodeGenPrepare/AArch64/large-offset-gep-pr43269.ll


Index: llvm/test/Transforms/CodeGenPrepare/AArch64/large-offset-gep-pr43269.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/CodeGenPrepare/AArch64/large-offset-gep-pr43269.ll
@@ -0,0 +1,52 @@
+; RUN: opt -mtriple=aarch64-linux-gnu --codegenprepare -S %s | FileCheck %s
+
+; Just don't crash, see PR43269.
+; CHECK: @t
+
+%struct.f = type { [1024 x %struct.b] }
+%struct.b = type { i32, i32, i32, i32 }
+ at o = common local_unnamed_addr global i32 0, align 4
+ at p = common local_unnamed_addr global i32 0, align 4
+ at j = common global %struct.f zeroinitializer, align 4
+
+
+define i32 @t() local_unnamed_addr {
+entry:
+  %call = tail call i8* bitcast (i8* (...)* @s to i8* ()*)()
+  %0 = load i32, i32* @o, align 4
+  %tobool = icmp eq i32 %0, 0
+  br i1 %tobool, label %if.end, label %bad
+
+if.end:
+  %n = getelementptr inbounds i8, i8* %call, i64 16392
+  %1 = bitcast i8* %n to i32*
+  %2 = load i32, i32* @p, align 4
+  %m = getelementptr inbounds i8, i8* %call, i64 16384
+  %arrayidx = bitcast i8* %m to i8**
+  %call5 = tail call i32 bitcast (i32 (...)* @q to i32 (i32, i32, i32, void (%struct.f*, ...)*, i32, %struct.f*, i8**)*)(i32 0, i32 %2, i32 0, void (%struct.f*, ...)* nonnull @h, i32 0, %struct.f* nonnull @j, i8** nonnull %arrayidx)
+  %call7 = tail call i32 bitcast (i32 (...)* @q to i32 ()*)()
+  %tobool8 = icmp eq i32 %call7, 0
+  br i1 %tobool8, label %if.end10, label %if.then9
+
+if.then9:
+  tail call void bitcast (void (...)* @r to void ()*)()
+  br label %if.end10
+
+if.end10:
+  %3 = load i32, i32* %1, align 8
+  %tobool12 = icmp eq i32 %3, 0
+  %4 = load i32, i32* @p, align 4
+  %arrayidx19 = bitcast i8* %m to i8**
+  %arrayidx19.sink = select i1 %tobool12, i8** %arrayidx19, i8** %arrayidx
+  %5 = load i8*, i8** %arrayidx19.sink, align 8
+  tail call void bitcast (void (...)* @r to void (i32, i32, i8*)*)(i32 0, i32 %4, i8* %5)
+  br label %bad
+
+bad:
+  ret i32 0
+}
+
+declare i8* @s(...)
+declare i32 @q(...)
+declare void @h(%struct.f* sret %0, ...)
+declare void @r(...)
Index: llvm/lib/CodeGen/CodeGenPrepare.cpp
===================================================================
--- llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -5108,6 +5108,12 @@
     WeakTrackingVH IterHandle(CurValue);
     BasicBlock *BB = CurInstIterator->getParent();
 
+    // These maps can have an AssertingVH to a GEP that gets recursively
+    // deleted below; see PR43269. Clearing them is okay: since we return
+    // true below, the optimization will be re-run.
+    LargeOffsetGEPMap.clear();
+    LargeOffsetGEPID.clear();
+
     RecursivelyDeleteTriviallyDeadInstructions(Repl, TLInfo);
 
     if (IterHandle != CurValue) {


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