Make Value::isDereferenceablePointer() handle unreachable code blocks. (This

returns false in the event the computation feeding into the pointer is
unreachable, which maybe ought to be true -- but this is at least consistent
with undef->isDereferenceablePointer().) Fixes PR11825!

llvm-svn: 148671

1 files changed, 28 insertions, 0 deletions

diff --git a/llvm/test/Transforms/SimplifyCFG/unreachable-blocks.ll b/llvm/test/Transforms/SimplifyCFG/unreachable-blocks.ll
new file mode 100644
index 00000000000..1df0eab6259
--- /dev/null
+++ b/llvm/test/Transforms/SimplifyCFG/unreachable-blocks.ll
@@ -0,0 +1,28 @@
+; RUN: opt -simplifycfg < %s -disable-output
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
+target triple = "x86_64-pc-linux-gnu"
+
+; PR11825
+define void @test1() {
+entry:
+  br label %return
+
+while_block:                                      ; preds = %and_if_cont2, %and_if_cont
+  %newlen = sub i32 %newlen, 1
+  %newptr = getelementptr i8* %newptr, i64 1
+  %test = icmp sgt i32 %newlen, 0
+  br i1 %test, label %and_if1, label %and_if_cont2
+
+and_if1:                                          ; preds = %while_block
+  %char = load i8* %newptr
+  %test2 = icmp ule i8 %char, 32
+  br label %and_if_cont2
+
+and_if_cont2:                                     ; preds = %and_if1, %while_block
+  %a18 = phi i1 [ %test, %while_block ], [ %test2, %and_if1 ]
+  br i1 %a18, label %while_block, label %return
+
+return:                                           ; preds = %and_if_cont2, %and_if_cont
+  ret void
+}