[MemorySSA] Moving at the end often means before terminator.

Moving accesses in MemorySSA at InsertionPlace::End, when an instruction is
moved into a block, almost always means insert at the end of the block, but
before the block terminator. This matters when the block terminator is a
MemoryAccess itself (an invoke), and the insertion must be done before
the terminator for the update to be correct.

Insert an additional position: InsertionPlace:BeforeTerminator and update
current usages where this applies.

Resolves PR44027.

1 files changed, 27 insertions, 0 deletions

diff --git a/llvm/test/Analysis/MemorySSA/pr44027.ll b/llvm/test/Analysis/MemorySSA/pr44027.ll
new file mode 100644
index 00000000000..3c0f9266ca2
--- /dev/null
+++ b/llvm/test/Analysis/MemorySSA/pr44027.ll
@@ -0,0 +1,27 @@
+; RUN: opt -gvn-hoist -verify-memoryssa -S < %s | FileCheck %s
+; REQUIRES: asserts
+
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+declare i32 @wobble(...)
+
+declare void @spam() align 2
+
+; CHECK-LABEL: @f()
+define void @f() personality i8* bitcast (i32 (...)* @wobble to i8*) {
+bb:
+  %tmp = alloca i32*, align 8
+  invoke void @spam()
+          to label %bb16 unwind label %bb23
+
+bb16:                                             ; preds = %bb
+  %tmp17 = load i32*, i32** %tmp, align 8
+  %tmp18 = load i32*, i32** %tmp, align 8
+  unreachable
+
+bb23:                                             ; preds = %bb
+  %tmp24 = landingpad { i8*, i32 }
+          cleanup
+  unreachable
+}