SCEV fix: Handle loop invariant loads.

Fixes PR11882: NULL dereference in ComputeLoadConstantCompareExitLimit.

llvm-svn: 153480

1 files changed, 47 insertions, 0 deletions

diff --git a/llvm/test/Analysis/ScalarEvolution/2012-03-26-LoadConstant.ll b/llvm/test/Analysis/ScalarEvolution/2012-03-26-LoadConstant.ll
new file mode 100644
index 00000000000..138c015f12c
--- /dev/null
+++ b/llvm/test/Analysis/ScalarEvolution/2012-03-26-LoadConstant.ll
@@ -0,0 +1,47 @@
+; RUN: opt < %s -basicaa -globalopt -instcombine -loop-rotate -licm -instcombine -indvars -loop-deletion -constmerge -S
+; PR11882: ComputeLoadConstantCompareExitLimit crash.
+;
+; for.body is deleted leaving a loop-invariant load.
+; CHECK-NOT: for.body
+target datalayout = "e-p:64:64:64-n32:64"
+
+@func_21_l_773 = external global i32, align 4
+@g_814 = external global i32, align 4
+@g_244 = internal global [1 x [0 x i32]] zeroinitializer, align 4
+
+define void @func_21() nounwind uwtable ssp {
+entry:
+  br label %lbl_818
+
+lbl_818:                                          ; preds = %for.end, %entry
+  call void (...)* @func_27()
+  store i32 0, i32* @g_814, align 4, !tbaa !0
+  br label %for.cond
+
+for.cond:                                         ; preds = %for.body, %lbl_818
+  %0 = load i32* @g_814, align 4, !tbaa !0
+  %cmp = icmp sle i32 %0, 0
+  br i1 %cmp, label %for.body, label %for.end
+
+for.body:                                         ; preds = %for.cond
+  %idxprom = sext i32 %0 to i64
+  %arrayidx = getelementptr inbounds [0 x i32]* getelementptr inbounds ([1 x [0 x i32]]* @g_244, i32 0, i64 0), i32 0, i64 %idxprom
+  %1 = load i32* %arrayidx, align 1, !tbaa !0
+  store i32 %1, i32* @func_21_l_773, align 4, !tbaa !0
+  store i32 1, i32* @g_814, align 4, !tbaa !0
+  br label %for.cond
+
+for.end:                                          ; preds = %for.cond
+  %2 = load i32* @func_21_l_773, align 4, !tbaa !0
+  %tobool = icmp ne i32 %2, 0
+  br i1 %tobool, label %lbl_818, label %if.end
+
+if.end:                                           ; preds = %for.end
+  ret void
+}
+
+declare void @func_27(...)
+
+!0 = metadata !{metadata !"int", metadata !1}
+!1 = metadata !{metadata !"omnipotent char", metadata !2}
+!2 = metadata !{metadata !"Simple C/C++ TBAA", null}