[PATCH] D121744: [SCCP] do not clean up dead blocks that have their address taken

[Nick Desaulniers via Phabricator via llvm-commits]

This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rGe1bae23f6f2b: [SCCP] do not clean up dead blocks that have their address taken (authored by nickdesaulniers).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D121744/new/

https://reviews.llvm.org/D121744

Files:
  llvm/lib/Transforms/Scalar/SCCP.cpp
  llvm/test/Transforms/SCCP/dangling-block-address.ll


Index: llvm/test/Transforms/SCCP/dangling-block-address.ll
===================================================================
--- llvm/test/Transforms/SCCP/dangling-block-address.ll
+++ llvm/test/Transforms/SCCP/dangling-block-address.ll
@@ -2,10 +2,13 @@
 ; RUN: opt -S -passes=internalize,ipsccp %s | FileCheck %s
 ; PR5569
 
-; IPSCCP should prove that the blocks are dead and delete them, and
-; properly handle the dangling blockaddress constants.
+; If BasicBlocks are unreachable, IPSCCP should convert them to unreachable.
+; Unless they have their address taken, delete them. If they do have their
+; address taken, let other passes replace these "dead" blockaddresses with some
+; other Constant.
+
+; CHECK: @bar.l = internal constant [2 x i8*] [i8* blockaddress(@bar, %lab0), i8* blockaddress(@bar, %end)]
 
-; CHECK: @bar.l = internal constant [2 x i8*] [i8* inttoptr (i32 1 to i8*), i8* inttoptr (i32 1 to i8*)]
 
 @code = global [5 x i32] [i32 0, i32 0, i32 0, i32 0, i32 1], align 4 ; <[5 x i32]*> [#uses=0]
 @bar.l = internal constant [2 x i8*] [i8* blockaddress(@bar, %lab0), i8* blockaddress(@bar, %end)] ; <[2 x i8*]*> [#uses=1]
@@ -25,6 +28,10 @@
 ; CHECK-LABEL: @bar(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    unreachable
+; CHECK:       lab0:
+; CHECK-NEXT:    unreachable
+; CHECK:       end:
+; CHECK-NEXT:    unreachable
 ;
 entry:
   br label %indirectgoto
@@ -53,3 +60,29 @@
 entry:
   ret i32 0
 }
+
+; https://github.com/llvm/llvm-project/issues/54238
+; https://github.com/llvm/llvm-project/issues/54251
+; https://github.com/llvm/llvm-project/issues/54328
+define i32 @test1() {
+; CHECK-LABEL: @test1(
+; CHECK-NEXT:    unreachable
+; CHECK:       redirected:
+; CHECK-NEXT:    unreachable
+;
+  %1 = bitcast i8* blockaddress(@test1, %redirected) to i64*
+  call void @set_return_addr(i64* %1)
+  ret i32 0
+
+redirected:
+  ret i32 0
+}
+
+define internal void @set_return_addr(i64* %addr) {
+; CHECK-LABEL: @set_return_addr(
+; CHECK-NEXT:    unreachable
+;
+  %addr.addr = alloca i64*, i32 0, align 8
+  store i64* %addr, i64** %addr.addr, align 8
+  ret void
+}
Index: llvm/lib/Transforms/Scalar/SCCP.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/SCCP.cpp
+++ llvm/lib/Transforms/Scalar/SCCP.cpp
@@ -530,7 +530,8 @@
       MadeChanges |= removeNonFeasibleEdges(Solver, &BB, DTU);
 
     for (BasicBlock *DeadBB : BlocksToErase)
-      DTU.deleteBB(DeadBB);
+      if (!DeadBB->hasAddressTaken())
+        DTU.deleteBB(DeadBB);
 
     for (BasicBlock &BB : F) {
       for (Instruction &Inst : llvm::make_early_inc_range(BB)) {


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