This fixes a bug introduced in 72661, which can

move loads back past a check that the load address
is valid, see new testcase.  The test that went
in with 72661 has exactly this case, except that
the conditional it's moving past is checking
something else; I've settled for changing that
test to reference a global, not a pointer.  It
may be possible to scan all the tests you pass and
make sure none of them are checking any component
of the address, but it's not trivial and I'm not
trying to do that here.

llvm-svn: 73632

2 files changed, 77 insertions, 4 deletions

diff --git a/llvm/test/Transforms/GVN/2009-06-17-InvalidPRE.ll b/llvm/test/Transforms/GVN/2009-06-17-InvalidPRE.ll
new file mode 100644
index 00000000000..c8982c86cb9
--- /dev/null
+++ b/llvm/test/Transforms/GVN/2009-06-17-InvalidPRE.ll
@@ -0,0 +1,72 @@
+; RUN: llvm-as < %s | opt -gvn -enable-load-pre | llvm-dis | not grep pre1
+; GVN load pre was hoisting the loads at %13 and %16 up to bb4.outer.  
+; This is invalid as it bypasses the check for %m.0.ph==null in bb4. 
+; ModuleID = 'mbuf.c'
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
+target triple = "i386-apple-darwin9.6"
+  %struct.mbuf = type { %struct.mbuf*, %struct.mbuf*, i32, i8*, i16, i16, i32 }
+
+define void @m_adj(%struct.mbuf* %mp, i32 %req_len) nounwind optsize {
+entry:
+  %0 = icmp eq %struct.mbuf* %mp, null    ; <i1> [#uses=1]
+  %1 = icmp slt i32 %req_len, 0   ; <i1> [#uses=1]
+  %or.cond = or i1 %1, %0   ; <i1> [#uses=1]
+  br i1 %or.cond, label %return, label %bb4.preheader
+
+bb4.preheader:    ; preds = %entry
+  br label %bb4.outer
+
+bb2:    ; preds = %bb1
+  %2 = sub i32 %len.0, %13   ; <i32> [#uses=1]
+  %3 = getelementptr %struct.mbuf* %m.0.ph, i32 0, i32 2    ; <i32*> [#uses=1]
+  store i32 0, i32* %3, align 4
+  %4 = getelementptr %struct.mbuf* %m.0.ph, i32 0, i32 0    ; <%struct.mbuf**> [#uses=1]
+  %5 = load %struct.mbuf** %4, align 4    ; <%struct.mbuf*> [#uses=1]
+  br label %bb4.outer
+
+bb4.outer:    ; preds = %bb4.preheader, %bb2
+  %m.0.ph = phi %struct.mbuf* [ %5, %bb2 ], [ %mp, %bb4.preheader ]   ; <%struct.mbuf*> [#uses=7]
+  %len.0.ph = phi i32 [ %2, %bb2 ], [ %req_len, %bb4.preheader ]    ; <i32> [#uses=1]
+  %6 = icmp ne %struct.mbuf* %m.0.ph, null    ; <i1> [#uses=1]
+  %7 = getelementptr %struct.mbuf* %m.0.ph, i32 0, i32 2    ; <i32*> [#uses=1]
+  %8 = getelementptr %struct.mbuf* %m.0.ph, i32 0, i32 2   ; <i32*> [#uses=1]
+  %9 = getelementptr %struct.mbuf* %m.0.ph, i32 0, i32 3   ; <i8**> [#uses=1]
+  %10 = getelementptr %struct.mbuf* %m.0.ph, i32 0, i32 3   ; <i8**> [#uses=1]
+  br label %bb4
+
+bb4:    ; preds = %bb4.outer, %bb3
+  %len.0 = phi i32 [ 0, %bb3 ], [ %len.0.ph, %bb4.outer ]   ; <i32> [#uses=6]
+  %11 = icmp sgt i32 %len.0, 0    ; <i1> [#uses=1]
+  %12 = and i1 %11, %6    ; <i1> [#uses=1]
+  br i1 %12, label %bb1, label %bb7
+
+bb1:    ; preds = %bb4
+  %13 = load i32* %7, align 4    ; <i32> [#uses=3]
+  %14 = icmp sgt i32 %13, %len.0    ; <i1> [#uses=1]
+  br i1 %14, label %bb3, label %bb2
+
+bb3:    ; preds = %bb1
+  %15 = sub i32 %13, %len.0    ; <i32> [#uses=1]
+  store i32 %15, i32* %8, align 4
+  %16 = load i8** %9, align 4    ; <i8*> [#uses=1]
+  %17 = getelementptr i8* %16, i32 %len.0   ; <i8*> [#uses=1]
+  store i8* %17, i8** %10, align 4
+  br label %bb4
+
+bb7:    ; preds = %bb4
+  %18 = getelementptr %struct.mbuf* %mp, i32 0, i32 5   ; <i16*> [#uses=1]
+  %19 = load i16* %18, align 2    ; <i16> [#uses=1]
+  %20 = zext i16 %19 to i32   ; <i32> [#uses=1]
+  %21 = and i32 %20, 2    ; <i32> [#uses=1]
+  %22 = icmp eq i32 %21, 0    ; <i1> [#uses=1]
+  br i1 %22, label %return, label %bb8
+
+bb8:    ; preds = %bb7
+  %23 = sub i32 %req_len, %len.0    ; <i32> [#uses=1]
+  %24 = getelementptr %struct.mbuf* %mp, i32 0, i32 6   ; <i32*> [#uses=1]
+  store i32 %23, i32* %24, align 4
+  ret void
+
+return:   ; preds = %bb7, %entry
+  ret void
+}
diff --git a/llvm/test/Transforms/GVN/pre-single-pred.ll b/llvm/test/Transforms/GVN/pre-single-pred.ll
index b735ea9827c..cb71617caed 100644
--- a/llvm/test/Transforms/GVN/pre-single-pred.ll
+++ b/llvm/test/Transforms/GVN/pre-single-pred.ll
@@ -1,6 +1,7 @@
 ; RUN: llvm-as < %s | opt -gvn -enable-load-pre | llvm-dis | not grep {tmp3 = load}
 
-define i32 @f(i32* nocapture %p, i32 %n) nounwind {
+@p = external global i32
+define i32 @f(i32 %n) nounwind {
 entry:
 	br label %for.cond
 
@@ -13,9 +14,9 @@ for.cond.for.end_crit_edge:		; preds = %for.cond
 	br label %for.end
 
 for.body:		; preds = %for.cond
-	%tmp3 = load i32* %p		; <i32> [#uses=1]
+	%tmp3 = load i32* @p		; <i32> [#uses=1]
 	%dec = add i32 %tmp3, -1		; <i32> [#uses=2]
-	store i32 %dec, i32* %p
+	store i32 %dec, i32* @p
 	%cmp6 = icmp slt i32 %dec, 0		; <i1> [#uses=1]
 	br i1 %cmp6, label %for.body.for.end_crit_edge, label %for.inc
 
@@ -27,6 +28,6 @@ for.inc:		; preds = %for.body
 	br label %for.cond
 
 for.end:		; preds = %for.body.for.end_crit_edge, %for.cond.for.end_crit_edge
-	%tmp9 = load i32* %p		; <i32> [#uses=1]
+	%tmp9 = load i32* @p		; <i32> [#uses=1]
 	ret i32 %tmp9
 }