[PATCH] D55729: [CodeGenPrepare] Fix bad IR created by large offset GEP splitting.

[Eli Friedman via Phabricator via llvm-commits]

efriedma created this revision.
efriedma added reviewers: dmgreen, spatel, mcrosier.
Herald added a subscriber: javed.absar.

Creating the IR builder, then modifying the CFG, leads to an IRBuilder where the BB and insertion point are inconsistent, so new instructions have the wrong parent.

Modified an existing test because the test wasn't covering anything useful (the "invoke" was not actually an invoke by the time we hit the code in question).

It would be nice if IRBuilder could give an assertion for this, somehow... I'll think about it.


Repository:
  rL LLVM

https://reviews.llvm.org/D55729

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


Index: test/Transforms/CodeGenPrepare/AArch64/large-offset-gep.ll
===================================================================
--- test/Transforms/CodeGenPrepare/AArch64/large-offset-gep.ll
+++ test/Transforms/CodeGenPrepare/AArch64/large-offset-gep.ll
@@ -88,18 +88,23 @@
 }
 
 declare %struct_type* @foo()
+declare void @foo2()
 
 define void @test4(i32 %n) personality i32 (...)* @__FrameHandler {
 ; CHECK-LABEL: test4
 entry:
-  %struct = invoke %struct_type* @foo() to label %while_cond unwind label %cleanup
+  br label %while_cond
 
 while_cond:
   %phi = phi i32 [ 0, %entry ], [ %i, %while_body ]
+  %struct = invoke %struct_type* @foo() to label %while_cond_x unwind label %cleanup
+
+while_cond_x:
 ; CHECK:     mov     w{{[0-9]+}}, #40000
 ; CHECK-NOT: mov     w{{[0-9]+}}, #40004
   %gep0 = getelementptr %struct_type, %struct_type* %struct, i64 0, i32 1
   %gep1 = getelementptr %struct_type, %struct_type* %struct, i64 0, i32 2
+  store i32 0, i32* %gep0
   %cmp = icmp slt i32 %phi, %n
   br i1 %cmp, label %while_body, label %while_end
 
@@ -114,8 +119,10 @@
   ret void
 
 cleanup:
-  landingpad { i8*, i32 } cleanup
-  unreachable
+  %x10 = landingpad { i8*, i32 }
+          cleanup
+  call void @foo2()
+  resume { i8*, i32 } %x10
 }
 
 declare i32 @__FrameHandler(...)
Index: lib/CodeGen/CodeGenPrepare.cpp
===================================================================
--- lib/CodeGen/CodeGenPrepare.cpp
+++ lib/CodeGen/CodeGenPrepare.cpp
@@ -5160,11 +5160,11 @@
       }
 
       // Generate a new GEP to replace the current one.
-      IRBuilder<> Builder(GEP);
+      LLVMContext &Ctx = GEP->getContext();
       Type *IntPtrTy = DL->getIntPtrType(GEP->getType());
       Type *I8PtrTy =
-          Builder.getInt8PtrTy(GEP->getType()->getPointerAddressSpace());
-      Type *I8Ty = Builder.getInt8Ty();
+          Type::getInt8PtrTy(Ctx, GEP->getType()->getPointerAddressSpace());
+      Type *I8Ty = Type::getInt8Ty(Ctx);
 
       if (!NewBaseGEP) {
         // Create a new base if we don't have one yet.  Find the insertion
@@ -5200,6 +5200,7 @@
         NewGEPBases.insert(NewBaseGEP);
       }
 
+      IRBuilder<> Builder(GEP);
       Value *NewGEP = NewBaseGEP;
       if (Offset == BaseOffset) {
         if (GEP->getType() != I8PtrTy)


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