[llvm] 8bfef78 - [ConstantHoisting] Fix bug where constant materialization could insert into EH pad

[Reid Kleckner via llvm-commits]

Author: Michael Holman
Date: 2021-02-01T11:23:56-08:00
New Revision: 8bfef787225c14a67db23254b82b330e85d1c35c

URL: https://github.com/llvm/llvm-project/commit/8bfef787225c14a67db23254b82b330e85d1c35c
DIFF: https://github.com/llvm/llvm-project/commit/8bfef787225c14a67db23254b82b330e85d1c35c.diff

LOG: [ConstantHoisting] Fix bug where constant materialization could insert into EH pad

If the incoming block to a phi node is an EH pad, then we will
materialize into an EH pad, which is not supposed to happen. To fix
this, I added a check to see if incoming block of a phi node is an EH
pad before using it as the insertion point.

Differential Revision: https://reviews.llvm.org/D95019

Added: 
    llvm/test/Transforms/ConstantHoisting/X86/ehphi.ll

Modified: 
    llvm/lib/Transforms/Scalar/ConstantHoisting.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Scalar/ConstantHoisting.cpp b/llvm/lib/Transforms/Scalar/ConstantHoisting.cpp
index fdab74fc94c5..80d9e5ab7b23 100644
--- a/llvm/lib/Transforms/Scalar/ConstantHoisting.cpp
+++ b/llvm/lib/Transforms/Scalar/ConstantHoisting.cpp
@@ -185,13 +185,20 @@ Instruction *ConstantHoistingPass::findMatInsertPt(Instruction *Inst,
   // We can't insert directly before a phi node or an eh pad. Insert before
   // the terminator of the incoming or dominating block.
   assert(Entry != Inst->getParent() && "PHI or landing pad in entry block!");
-  if (Idx != ~0U && isa<PHINode>(Inst))
-    return cast<PHINode>(Inst)->getIncomingBlock(Idx)->getTerminator();
+  BasicBlock *InsertionBlock = nullptr;
+  if (Idx != ~0U && isa<PHINode>(Inst)) {
+    InsertionBlock = cast<PHINode>(Inst)->getIncomingBlock(Idx);
+    if (!InsertionBlock->isEHPad()) {
+      return InsertionBlock->getTerminator();
+    }
+  } else {
+    InsertionBlock = Inst->getParent();
+  }
 
   // This must be an EH pad. Iterate over immediate dominators until we find a
   // non-EH pad. We need to skip over catchswitch blocks, which are both EH pads
   // and terminators.
-  auto IDom = DT->getNode(Inst->getParent())->getIDom();
+  auto *IDom = DT->getNode(InsertionBlock)->getIDom();
   while (IDom->getBlock()->isEHPad()) {
     assert(Entry != IDom->getBlock() && "eh pad in entry block");
     IDom = IDom->getIDom();

diff  --git a/llvm/test/Transforms/ConstantHoisting/X86/ehphi.ll b/llvm/test/Transforms/ConstantHoisting/X86/ehphi.ll
new file mode 100644
index 000000000000..bf18733d344c
--- /dev/null
+++ b/llvm/test/Transforms/ConstantHoisting/X86/ehphi.ll
@@ -0,0 +1,58 @@
+; RUN: opt -S -consthoist < %s | FileCheck %s
+
+target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-windows-msvc"
+
+define internal fastcc void @baz(i8* %arg) unnamed_addr personality i8* bitcast (i32 (...)* @wobble to i8*) {
+; CHECK-LABEL:  @baz
+bb:
+  %tmp = invoke noalias dereferenceable(40) i8* @wibble.2(i64 40)
+          to label %bb6 unwind label %bb1
+
+bb1:                                              ; preds = %bb
+; CHECK: bb1:
+; CHECK-NEXT:  %tmp2 = catchswitch within none [label %bb3] unwind label %bb16
+  %tmp2 = catchswitch within none [label %bb3] unwind label %bb16
+
+bb3:                                              ; preds = %bb1
+  %tmp4 = catchpad within %tmp2 [i8* null, i32 64, i8* null]
+  invoke void @spam(i8* null) [ "funclet"(token %tmp4) ]
+          to label %bb5 unwind label %bb16
+
+bb5:                                              ; preds = %bb3
+  unreachable
+
+bb6:                                              ; preds = %bb
+  %tmp7 = icmp eq i8* %arg, null
+  br label %bb9
+
+
+bb9:                                              ; preds = %bb8, %bb6
+  %tmp10 = inttoptr i64 -6148914691236517376 to i16*
+  %tmp11 = invoke noalias dereferenceable(40) i8* @wibble.2(i64 40)
+          to label %bb15 unwind label %bb12
+
+bb12:                                             ; preds = %bb9
+  %tmp13 = cleanuppad within none []
+  br label %bb14
+
+bb14:                                             ; preds = %bb12
+  cleanupret from %tmp13 unwind label %bb16
+
+bb15:                                             ; preds = %bb9
+  ret void
+
+bb16:                                             ; preds = %bb14, %bb3, %bb1
+  %tmp17 = phi i16* [ inttoptr (i64 -6148914691236517376 to i16*), %bb1 ], [ inttoptr (i64 -6148914691236517376 to i16*), %bb3 ], [ %tmp10, %bb14 ]
+  %tmp18 = cleanuppad within none []
+  br label %bb19
+
+bb19:                                             ; preds = %bb16
+  cleanupret from %tmp18 unwind to caller
+}
+
+declare i8* @wibble.2(i64)
+
+declare dso_local void @spam(i8*) local_unnamed_addr
+
+declare i32 @wobble(...)