Now that instruction optzns can update the iterator as they go, we can

have objectsize folding recursively simplify away their result when it
folds.  It is important to catch this here, because otherwise we won't
eliminate the cross-block values at isel and other times.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123524 91177308-0d34-0410-b5e6-96231b3b80d8

test/Transforms/CodeGenPrepare/basic.ll

@@ -0,0 +1,24 @@
+; RUN: opt -codegenprepare %s -S -o - | FileCheck %s
+
+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-apple-darwin10.0.0"
+
+; CHECK: @test1
+define i32 @test1(i8* %ptr) nounwind ssp noredzone align 2 {
+entry:
+  %0 = tail call i64 @llvm.objectsize.i64(i8* %ptr, i1 false)
+  %1 = icmp ugt i64 %0, 3
+  br i1 %1, label %T, label %trap
+
+; CHECK: br i1 true, label
+trap:                                             ; preds = %0, %entry
+  tail call void @llvm.trap() noreturn nounwind
+  unreachable
+
+T:
+  ret i32 4
+}
+
+declare i64 @llvm.objectsize.i64(i8*, i1) nounwind readonly
+
+declare void @llvm.trap() nounwind