llvm: Add support for "-fno-delete-null-pointer-checks"

Summary:
Support for this option is needed for building Linux kernel.
This is a very frequently requested feature by kernel developers.

More details : https://lkml.org/lkml/2018/4/4/601

GCC option description for -fdelete-null-pointer-checks:
This Assume that programs cannot safely dereference null pointers,
and that no code or data element resides at address zero.

-fno-delete-null-pointer-checks is the inverse of this implying that
null pointer dereferencing is not undefined.

This feature is implemented in LLVM IR in this CL as the function attribute
"null-pointer-is-valid"="true" in IR (Under review at D47894).
The CL updates several passes that assumed null pointer dereferencing is
undefined to not optimize when the "null-pointer-is-valid"="true"
attribute is present.

Reviewers: t.p.northover, efriedma, jyknight, chandlerc, rnk, srhines, void, george.burgess.iv

Reviewed By: efriedma, george.burgess.iv

Subscribers: eraman, haicheng, george.burgess.iv, drinkcat, theraven, reames, sanjoy, xbolva00, llvm-commits

Differential Revision: https://reviews.llvm.org/D47895

llvm-svn: 336613

18 files changed, 456 insertions, 1 deletions

diff --git a/llvm/test/Transforms/GlobalOpt/MallocSROA-section-no-null-opt.ll b/llvm/test/Transforms/GlobalOpt/MallocSROA-section-no-null-opt.ll
new file mode 100644
index 00000000000..c9b3f6fc1cd
--- /dev/null
+++ b/llvm/test/Transforms/GlobalOpt/MallocSROA-section-no-null-opt.ll
@@ -0,0 +1,34 @@
+; RUN: opt -globalopt -S < %s | FileCheck %s
+; CHECK: @Y
+; CHECK: section ".foo"
+
+%struct.xyz = type { double, i32 }
+
+@Y = internal global %struct.xyz* null ,section ".foo"            ; <%struct.xyz**> [#uses=2]
+@numf2s = external global i32                     ; <i32*> [#uses=1]
+
+define void @init_net() #0 {
+; CHECK-LABEL: init_net(
+; CHECK: load i32, i32* @numf2s
+; CHECK: call i8* @malloc
+; CHECK: store %struct.xyz* {{.*}}, %struct.xyz** @Y
+entry:
+  %0 = load i32, i32* @numf2s, align 4                 ; <i32> [#uses=1]
+  %mallocsize2 = shl i32 %0, 4                    ; <i32> [#uses=1]
+  %malloccall3 = tail call i8* @malloc(i32 %mallocsize2)  ; <i8*> [#uses=1]
+  %1 = bitcast i8* %malloccall3 to %struct.xyz*   ; <%struct.xyz*> [#uses=1]
+  store %struct.xyz* %1, %struct.xyz** @Y, align 8
+  ret void
+}
+
+define %struct.xyz* @load_train() #0 {
+; CHECK-LABEL: load_train(
+; CHECK: load %struct.xyz*, %struct.xyz** @Y
+entry:
+  %0 = load %struct.xyz*, %struct.xyz** @Y, align 8             ; <%struct.xyz*> [#uses=0]
+  ret %struct.xyz* %0
+}
+
+declare noalias i8* @malloc(i32)
+
+attributes #0 = { "null-pointer-is-valid"="true" }
diff --git a/llvm/test/Transforms/GlobalOpt/heap-sra-1-no-null-opt.ll b/llvm/test/Transforms/GlobalOpt/heap-sra-1-no-null-opt.ll
new file mode 100644
index 00000000000..c826e7f7a04
--- /dev/null
+++ b/llvm/test/Transforms/GlobalOpt/heap-sra-1-no-null-opt.ll
@@ -0,0 +1,40 @@
+; RUN: opt < %s -globalopt -S | FileCheck %s
+target datalayout = "E-p:64:64:64-a0:0:8-f32:32:32-f64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-v64:64:64-v128:128:128"
+
+%struct.foo = type { i32, i32 }
+@X = internal global %struct.foo* null
+; CHECK: @X
+; CHECK-NOT: @X.f0
+
+define void @bar(i64 %Size) nounwind noinline #0 {
+entry:
+  %mallocsize = mul i64 %Size, 8                  ; <i64> [#uses=1]
+  %malloccall = tail call i8* @malloc(i64 %mallocsize) ; <i8*> [#uses=1]
+  %.sub = bitcast i8* %malloccall to %struct.foo* ; <%struct.foo*> [#uses=1]
+	store %struct.foo* %.sub, %struct.foo** @X, align 4
+	ret void
+}
+
+declare noalias i8* @malloc(i64)
+
+define i32 @baz() nounwind readonly noinline #0 {
+bb1.thread:
+	%0 = load %struct.foo*, %struct.foo** @X, align 4
+	br label %bb1
+
+bb1:		; preds = %bb1, %bb1.thread
+	%i.0.reg2mem.0 = phi i32 [ 0, %bb1.thread ], [ %indvar.next, %bb1 ]
+	%sum.0.reg2mem.0 = phi i32 [ 0, %bb1.thread ], [ %3, %bb1 ]
+	%1 = getelementptr %struct.foo, %struct.foo* %0, i32 %i.0.reg2mem.0, i32 0
+	%2 = load i32, i32* %1, align 4
+	%3 = add i32 %2, %sum.0.reg2mem.0
+	%indvar.next = add i32 %i.0.reg2mem.0, 1
+	%exitcond = icmp eq i32 %indvar.next, 1200
+	br i1 %exitcond, label %bb2, label %bb1
+
+bb2:		; preds = %bb1
+	ret i32 %3
+}
+
+attributes #0 = { "null-pointer-is-valid"="true" }
+
diff --git a/llvm/test/Transforms/GlobalOpt/heap-sra-1.ll b/llvm/test/Transforms/GlobalOpt/heap-sra-1.ll
index 6035eaaefcc..28a20ada03f 100644
--- a/llvm/test/Transforms/GlobalOpt/heap-sra-1.ll
+++ b/llvm/test/Transforms/GlobalOpt/heap-sra-1.ll
@@ -36,3 +36,10 @@ bb2:		; preds = %bb1
 	ret i32 %3
 }
 
+define void @bam(i64 %Size) nounwind noinline #0 {
+entry:
+	%0 = load %struct.foo*, %struct.foo** @X, align 4
+        ret void
+}
+
+attributes #0 = { "null-pointer-is-valid"="true" }
diff --git a/llvm/test/Transforms/GlobalOpt/heap-sra-2-no-null-opt.ll b/llvm/test/Transforms/GlobalOpt/heap-sra-2-no-null-opt.ll
new file mode 100644
index 00000000000..c33bcba9921
--- /dev/null
+++ b/llvm/test/Transforms/GlobalOpt/heap-sra-2-no-null-opt.ll
@@ -0,0 +1,39 @@
+; RUN: opt < %s -globalopt -S | FileCheck %s
+target datalayout = "E-p:64:64:64-a0:0:8-f32:32:32-f64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-v64:64:64-v128:128:128"
+
+%struct.foo = type { i32, i32 }
+@X = internal global %struct.foo* null		; <%struct.foo**> [#uses=2]
+; CHECK: @X
+; CHECK-NOT: @X.f0
+
+define void @bar(i32 %Size) nounwind noinline #0 {
+entry:
+	%malloccall = tail call i8* @malloc(i64 8000000) ; <i8*> [#uses=1]
+	%0 = bitcast i8* %malloccall to [1000000 x %struct.foo]* ; <[1000000 x %struct.foo]*> [#uses=1]
+	%.sub = getelementptr [1000000 x %struct.foo], [1000000 x %struct.foo]* %0, i32 0, i32 0		; <%struct.foo*> [#uses=1]
+	store %struct.foo* %.sub, %struct.foo** @X, align 4
+	ret void
+}
+
+declare noalias i8* @malloc(i64)
+
+define i32 @baz() nounwind readonly noinline #0 {
+bb1.thread:
+	%0 = load %struct.foo*, %struct.foo** @X, align 4		; <%struct.foo*> [#uses=1]
+	br label %bb1
+
+bb1:		; preds = %bb1, %bb1.thread
+	%i.0.reg2mem.0 = phi i32 [ 0, %bb1.thread ], [ %indvar.next, %bb1 ]		; <i32> [#uses=2]
+	%sum.0.reg2mem.0 = phi i32 [ 0, %bb1.thread ], [ %3, %bb1 ]		; <i32> [#uses=1]
+	%1 = getelementptr %struct.foo, %struct.foo* %0, i32 %i.0.reg2mem.0, i32 0		; <i32*> [#uses=1]
+	%2 = load i32, i32* %1, align 4		; <i32> [#uses=1]
+	%3 = add i32 %2, %sum.0.reg2mem.0		; <i32> [#uses=2]
+	%indvar.next = add i32 %i.0.reg2mem.0, 1		; <i32> [#uses=2]
+	%exitcond = icmp eq i32 %indvar.next, 1200		; <i1> [#uses=1]
+	br i1 %exitcond, label %bb2, label %bb1
+
+bb2:		; preds = %bb1
+	ret i32 %3
+}
+
+attributes #0 = { "null-pointer-is-valid"="true" }
diff --git a/llvm/test/Transforms/GlobalOpt/heap-sra-2.ll b/llvm/test/Transforms/GlobalOpt/heap-sra-2.ll
index d66c627b184..ec05b22b33b 100644
--- a/llvm/test/Transforms/GlobalOpt/heap-sra-2.ll
+++ b/llvm/test/Transforms/GlobalOpt/heap-sra-2.ll
@@ -36,3 +36,10 @@ bb2:		; preds = %bb1
 	ret i32 %3
 }
 
+define void @bam(i64 %Size) nounwind noinline #0 {
+entry:
+        %0 = load %struct.foo*, %struct.foo** @X, align 4
+        ret void
+}
+
+attributes #0 = { "null-pointer-is-valid"="true" }
diff --git a/llvm/test/Transforms/GlobalOpt/heap-sra-3-no-null-opt.ll b/llvm/test/Transforms/GlobalOpt/heap-sra-3-no-null-opt.ll
new file mode 100644
index 00000000000..ba3b0a418a1
--- /dev/null
+++ b/llvm/test/Transforms/GlobalOpt/heap-sra-3-no-null-opt.ll
@@ -0,0 +1,41 @@
+; RUN: opt < %s -globalopt -S | FileCheck %s
+target datalayout = "E-p:64:64:64-a0:0:8-f32:32:32-f64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-v64:64:64-v128:128:128"
+
+%struct.foo = type { i32, i32 }
+@X = internal global %struct.foo* null
+; CHECK: @X
+; CHECK-NOT: @X.f0
+
+define void @bar(i64 %Size) nounwind noinline #0 {
+entry:
+  %mallocsize = mul i64 8, %Size ; <i64> [#uses=1]
+; CHECK: mul i64 8, %Size
+  %malloccall = tail call i8* @malloc(i64 %mallocsize) ; <i8*> [#uses=1]
+  %.sub = bitcast i8* %malloccall to %struct.foo* ; <%struct.foo*> [#uses=1]
+	store %struct.foo* %.sub, %struct.foo** @X, align 4
+	ret void
+}
+
+declare noalias i8* @malloc(i64)
+
+define i32 @baz() nounwind readonly noinline #0 {
+bb1.thread:
+; CHECK: load %struct.foo*, %struct.foo** @X, align 4
+	%0 = load %struct.foo*, %struct.foo** @X, align 4
+	br label %bb1
+
+bb1:		; preds = %bb1, %bb1.thread
+	%i.0.reg2mem.0 = phi i32 [ 0, %bb1.thread ], [ %indvar.next, %bb1 ]
+	%sum.0.reg2mem.0 = phi i32 [ 0, %bb1.thread ], [ %3, %bb1 ]
+	%1 = getelementptr %struct.foo, %struct.foo* %0, i32 %i.0.reg2mem.0, i32 0
+	%2 = load i32, i32* %1, align 4
+	%3 = add i32 %2, %sum.0.reg2mem.0
+	%indvar.next = add i32 %i.0.reg2mem.0, 1
+	%exitcond = icmp eq i32 %indvar.next, 1200
+	br i1 %exitcond, label %bb2, label %bb1
+
+bb2:		; preds = %bb1
+	ret i32 %3
+}
+
+attributes #0 = { "null-pointer-is-valid"="true" }
diff --git a/llvm/test/Transforms/GlobalOpt/heap-sra-3.ll b/llvm/test/Transforms/GlobalOpt/heap-sra-3.ll
index 6a34364b49f..67058c8aba2 100644
--- a/llvm/test/Transforms/GlobalOpt/heap-sra-3.ll
+++ b/llvm/test/Transforms/GlobalOpt/heap-sra-3.ll
@@ -37,3 +37,10 @@ bb2:		; preds = %bb1
 	ret i32 %3
 }
 
+define void @bam(i64 %Size) nounwind noinline #0 {
+entry:
+        %0 = load %struct.foo*, %struct.foo** @X, align 4
+        ret void
+}
+
+attributes #0 = { "null-pointer-is-valid"="true" }
diff --git a/llvm/test/Transforms/GlobalOpt/heap-sra-4-no-null-opt.ll b/llvm/test/Transforms/GlobalOpt/heap-sra-4-no-null-opt.ll
new file mode 100644
index 00000000000..607c93d1e8a
--- /dev/null
+++ b/llvm/test/Transforms/GlobalOpt/heap-sra-4-no-null-opt.ll
@@ -0,0 +1,44 @@
+; RUN: opt < %s -globalopt -S | FileCheck %s
+target datalayout = "E-p:64:64:64-a0:0:8-f32:32:32-f64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-v64:64:64-v128:128:128"
+
+%struct.foo = type { i32, i32 }
+
+@X = internal global %struct.foo* null
+; CHECK: @X
+; CHECK-NOT: @X.f0
+
+define void @bar(i64 %Size) nounwind noinline #0 {
+entry:
+  %mallocsize = shl i64 %Size, 3                  ; <i64> [#uses=1]
+  %malloccall = tail call i8* @malloc(i64 %mallocsize) ; <i8*> [#uses=1]
+; CHECK: shl i64 %Size, 3
+  %.sub = bitcast i8* %malloccall to %struct.foo* ; <%struct.foo*> [#uses=1]
+	store %struct.foo* %.sub, %struct.foo** @X, align 4
+	ret void
+}
+
+declare noalias i8* @malloc(i64)
+
+define i32 @baz() nounwind readonly noinline #0 {
+; CHECK-LABEL: @baz(
+bb1.thread:
+; CHECK: load %struct.foo*, %struct.foo** @X, align 4
+	%0 = load %struct.foo*, %struct.foo** @X, align 4
+	br label %bb1
+
+bb1:		; preds = %bb1, %bb1.thread
+	%i.0.reg2mem.0 = phi i32 [ 0, %bb1.thread ], [ %indvar.next, %bb1 ]
+	%sum.0.reg2mem.0 = phi i32 [ 0, %bb1.thread ], [ %3, %bb1 ]
+	%1 = getelementptr %struct.foo, %struct.foo* %0, i32 %i.0.reg2mem.0, i32 0
+	%2 = load i32, i32* %1, align 4
+; CHECK: load i32, i32* %1, align 4
+	%3 = add i32 %2, %sum.0.reg2mem.0
+	%indvar.next = add i32 %i.0.reg2mem.0, 1
+	%exitcond = icmp eq i32 %indvar.next, 1200
+	br i1 %exitcond, label %bb2, label %bb1
+
+bb2:		; preds = %bb1
+	ret i32 %3
+}
+
+attributes #0 = { "null-pointer-is-valid"="true" }
diff --git a/llvm/test/Transforms/GlobalOpt/heap-sra-4.ll b/llvm/test/Transforms/GlobalOpt/heap-sra-4.ll
index 2176b9fcbee..71832f34923 100644
--- a/llvm/test/Transforms/GlobalOpt/heap-sra-4.ll
+++ b/llvm/test/Transforms/GlobalOpt/heap-sra-4.ll
@@ -37,3 +37,11 @@ bb2:		; preds = %bb1
 	ret i32 %3
 }
 
+define void @bam(i64 %Size) nounwind noinline #0 {
+entry:
+        %0 = load %struct.foo*, %struct.foo** @X, align 4
+        ret void
+}
+
+attributes #0 = { "null-pointer-is-valid"="true" }
+
diff --git a/llvm/test/Transforms/GlobalOpt/heap-sra-phi-no-null-opt.ll b/llvm/test/Transforms/GlobalOpt/heap-sra-phi-no-null-opt.ll
new file mode 100644
index 00000000000..06c74e5bfc4
--- /dev/null
+++ b/llvm/test/Transforms/GlobalOpt/heap-sra-phi-no-null-opt.ll
@@ -0,0 +1,54 @@
+; RUN: opt < %s -globalopt -S | FileCheck %s
+target datalayout = "E-p:64:64:64-a0:0:8-f32:32:32-f64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-v64:64:64-v128:128:128"
+
+%struct.foo = type { i32, i32 }
+
+@X = internal global %struct.foo* null		; <%struct.foo**> [#uses=2]
+; CHECK: @X
+; CHECK-NOT: @X.f0
+
+define void @bar(i32 %Size) nounwind noinline #0 {
+;  CHECK-LABEL: @bar(
+entry:
+	%malloccall = tail call i8* @malloc(i64 8000000) ; <i8*> [#uses=1]
+	%tmp = bitcast i8* %malloccall to [1000000 x %struct.foo]* ; <[1000000 x %struct.foo]*> [#uses=1]
+	%.sub = getelementptr [1000000 x %struct.foo], [1000000 x %struct.foo]* %tmp, i32 0, i32 0		; <%struct.foo*> [#uses=1]
+	store %struct.foo* %.sub, %struct.foo** @X, align 4
+	ret void
+}
+
+declare noalias i8* @malloc(i64)
+
+define i32 @baz() nounwind readonly noinline #0 {
+; CHECK-LABEL: @baz(
+bb1.thread:
+	%tmpLD1 = load %struct.foo*, %struct.foo** @X, align 4		; <%struct.foo*> [#uses=1]
+; CHECK: load %struct.foo*, %struct.foo** @X, align 4
+	br label %bb1
+
+bb1:		; preds = %bb1, %bb1.thread
+        %tmp = phi %struct.foo* [%tmpLD1, %bb1.thread ], [ %tmpLD2, %bb1 ]		; <i32> [#uses=2]
+; CHECK: %tmp = phi %struct.foo* [ %tmpLD1, %bb1.thread ], [ %tmpLD2, %bb1 ]
+	%i.0.reg2mem.0 = phi i32 [ 0, %bb1.thread ], [ %indvar.next, %bb1 ]		; <i32> [#uses=2]
+	%sum.0.reg2mem.0 = phi i32 [ 0, %bb1.thread ], [ %tmp3, %bb1 ]		; <i32> [#uses=1]
+	%tmp1 = getelementptr %struct.foo, %struct.foo* %tmp, i32 %i.0.reg2mem.0, i32 0		; <i32*> [#uses=1]
+	%tmp2 = load i32, i32* %tmp1, align 4		; <i32> [#uses=1]
+; CHECK: load i32, i32* %tmp1, align 4
+	%tmp6 = add i32 %tmp2, %sum.0.reg2mem.0		; <i32> [#uses=2]
+	%tmp4 = getelementptr %struct.foo, %struct.foo* %tmp, i32 %i.0.reg2mem.0, i32 1		; <i32*> [#uses=1]
+        %tmp5 = load i32 , i32 * %tmp4
+;  CHECK: load i32, i32* %tmp4
+        %tmp3 = add i32 %tmp5, %tmp6
+	%indvar.next = add i32 %i.0.reg2mem.0, 1		; <i32> [#uses=2]
+
+      	%tmpLD2 = load %struct.foo*, %struct.foo** @X, align 4		; <%struct.foo*> [#uses=1]
+; CHECK: load %struct.foo*, %struct.foo** @X, align 4
+
+	%exitcond = icmp eq i32 %indvar.next, 1200		; <i1> [#uses=1]
+	br i1 %exitcond, label %bb2, label %bb1
+
+bb2:		; preds = %bb1
+	ret i32 %tmp3
+}
+
+attributes #0 = { "null-pointer-is-valid"="true" }
diff --git a/llvm/test/Transforms/GlobalOpt/heap-sra-phi.ll b/llvm/test/Transforms/GlobalOpt/heap-sra-phi.ll
index 995f9dc142c..770220dd07b 100644
--- a/llvm/test/Transforms/GlobalOpt/heap-sra-phi.ll
+++ b/llvm/test/Transforms/GlobalOpt/heap-sra-phi.ll
@@ -42,3 +42,11 @@ bb1:		; preds = %bb1, %bb1.thread
 bb2:		; preds = %bb1
 	ret i32 %tmp3
 }
+
+define void @bam(i64 %Size) nounwind noinline #0 {
+entry:
+        %0 = load %struct.foo*, %struct.foo** @X, align 4
+        ret void
+}
+
+attributes #0 = { "null-pointer-is-valid"="true" }
diff --git a/llvm/test/Transforms/GlobalOpt/load-store-global-no-null-opt.ll b/llvm/test/Transforms/GlobalOpt/load-store-global-no-null-opt.ll
new file mode 100644
index 00000000000..d319d162ff4
--- /dev/null
+++ b/llvm/test/Transforms/GlobalOpt/load-store-global-no-null-opt.ll
@@ -0,0 +1,28 @@
+; RUN: opt < %s -globalopt -S | FileCheck %s
+
+@a = internal global i64* null, align 8
+; CHECK: @a
+
+; PR13968
+define void @qux_no_null_opt() nounwind #0 {
+; CHECK-LABEL: @qux_no_null_opt(
+; CHECK: getelementptr i64*, i64** @a, i32 1
+; CHECK: store i64* inttoptr (i64 1 to i64*), i64** @a
+  %b = bitcast i64** @a to i8*
+  %g = getelementptr i64*, i64** @a, i32 1
+  %cmp = icmp ne i8* null, %b
+  %cmp2 = icmp eq i8* null, %b
+  %cmp3 = icmp eq i64** null, %g
+  store i64* inttoptr (i64 1 to i64*), i64** @a, align 8
+  %l = load i64*, i64** @a, align 8
+  ret void
+}
+
+define i64* @bar() {
+  %X = load i64*, i64** @a, align 8
+  ret i64* %X
+; CHECK-LABEL: @bar(
+; CHECK: load
+}
+
+attributes #0 = { "null-pointer-is-valid"="true" }
diff --git a/llvm/test/Transforms/GlobalOpt/malloc-promote-1-no-null-opt.ll b/llvm/test/Transforms/GlobalOpt/malloc-promote-1-no-null-opt.ll
new file mode 100644
index 00000000000..fc6dab31640
--- /dev/null
+++ b/llvm/test/Transforms/GlobalOpt/malloc-promote-1-no-null-opt.ll
@@ -0,0 +1,31 @@
+; RUN: opt < %s -globalopt -S | FileCheck %s
+target datalayout = "E-p:64:64:64-a0:0:8-f32:32:32-f64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-v64:64:64-v128:128:128"
+
+@G = internal global i32* null          ; <i32**> [#uses=3]
+; CHECK: global
+
+define void @init() #0 {
+; CHECK-LABEL: @init(
+; CHECK: store
+; CHECK: load
+        %malloccall = tail call i8* @malloc(i64 4)      ; <i8*> [#uses=1]
+        %P = bitcast i8* %malloccall to i32*            ; <i32*> [#uses=1]
+        store i32* %P, i32** @G
+        %GV = load i32*, i32** @G             ; <i32*> [#uses=1]
+        store i32 0, i32* %GV
+        ret void
+}
+
+declare noalias i8* @malloc(i64)
+
+define i32 @get() #0 {
+; CHECK-LABEL: @get(
+; CHECK: load i32*, i32** @G
+; CHECK-NEXT: load i32, i32* %GV
+        %GV = load i32*, i32** @G             ; <i32*> [#uses=1]
+        %V = load i32, i32* %GV              ; <i32> [#uses=1]
+        ret i32 %V
+; CHECK: ret i32 %V
+}
+
+attributes #0 = { "null-pointer-is-valid"="true" }
diff --git a/llvm/test/Transforms/GlobalOpt/malloc-promote-1.ll b/llvm/test/Transforms/GlobalOpt/malloc-promote-1.ll
index d5087dea344..a8f127474e3 100644
--- a/llvm/test/Transforms/GlobalOpt/malloc-promote-1.ll
+++ b/llvm/test/Transforms/GlobalOpt/malloc-promote-1.ll
@@ -1,7 +1,7 @@
 ; RUN: opt < %s -globalopt -S | FileCheck %s
 target datalayout = "E-p:64:64:64-a0:0:8-f32:32:32-f64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-v64:64:64-v128:128:128"
 
-@G = internal global i32* null          ; <i32**> [#uses=3]
+@G = internal global i32* null          ; <i32**> [#uses=4]
 ; CHECK-NOT: global
 
 define void @init() {
@@ -22,3 +22,11 @@ define i32 @get() {
 ; CHECK: ret i32 0
 }
 
+define void @foo(i64 %Size) nounwind noinline #0 {
+entry:
+        %0 = load i32*, i32** @G, align 4
+        ret void
+}
+
+attributes #0 = { "null-pointer-is-valid"="true" }
+
diff --git a/llvm/test/Transforms/GlobalOpt/malloc-promote-2-no-null-opt.ll b/llvm/test/Transforms/GlobalOpt/malloc-promote-2-no-null-opt.ll
new file mode 100644
index 00000000000..009a33435fd
--- /dev/null
+++ b/llvm/test/Transforms/GlobalOpt/malloc-promote-2-no-null-opt.ll
@@ -0,0 +1,24 @@
+; RUN: opt < %s -globalopt -S | FileCheck %s
+target datalayout = "E-p:64:64:64-a0:0:8-f32:32:32-f64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-v64:64:64-v128:128:128"
+
+@G = internal global i32* null
+
+define void @t() #0 {
+; CHECK: @t()
+; CHECK: call i8* @malloc
+; CHECK: bitcast
+; CHECK: store
+; CHECK: load
+; CHECK: getelementptr
+; CHECK: store
+  %malloccall = tail call i8* @malloc(i64 mul (i64 100, i64 4))
+  %P = bitcast i8* %malloccall to i32*
+  store i32* %P, i32** @G
+  %GV = load i32*, i32** @G
+  %GVe = getelementptr i32, i32* %GV, i32 40
+  store i32 20, i32* %GVe
+  ret void
+}
+
+declare noalias i8* @malloc(i64)
+attributes #0 = { "null-pointer-is-valid"="true" }
diff --git a/llvm/test/Transforms/GlobalOpt/malloc-promote-2.ll b/llvm/test/Transforms/GlobalOpt/malloc-promote-2.ll
index 335ed82a8cf..64f379365c7 100644
--- a/llvm/test/Transforms/GlobalOpt/malloc-promote-2.ll
+++ b/llvm/test/Transforms/GlobalOpt/malloc-promote-2.ll
@@ -17,3 +17,11 @@ define void @t() {
 }
 
 declare noalias i8* @malloc(i64)
+
+define void @foo(i64 %Size) nounwind noinline #0 {
+entry:
+        %0 = load i32*, i32** @G, align 4
+        ret void
+}
+
+attributes #0 = { "null-pointer-is-valid"="true" }
diff --git a/llvm/test/Transforms/GlobalOpt/storepointer-compare-no-null-opt.ll b/llvm/test/Transforms/GlobalOpt/storepointer-compare-no-null-opt.ll
new file mode 100644
index 00000000000..709df17e0b5
--- /dev/null
+++ b/llvm/test/Transforms/GlobalOpt/storepointer-compare-no-null-opt.ll
@@ -0,0 +1,40 @@
+; RUN: opt < %s -globalopt -S | FileCheck %s
+; CHECK: global
+
+@G = internal global void ()* null              ; <void ()**> [#uses=2]
+
+define internal void @Actual() {
+; CHECK-LABEL: Actual(
+        ret void
+}
+
+define void @init() {
+; CHECK-LABEL: init(
+; CHECK: store void ()* @Actual, void ()** @G
+        store void ()* @Actual, void ()** @G
+        ret void
+}
+
+define void @doit() #0 {
+; CHECK-LABEL: doit(
+        %FP = load void ()*, void ()** @G         ; <void ()*> [#uses=2]
+; CHECK: %FP = load void ()*, void ()** @G
+        %CC = icmp eq void ()* %FP, null                ; <i1> [#uses=1]
+; CHECK: %CC = icmp eq void ()* %FP, null
+        br i1 %CC, label %isNull, label %DoCall
+; CHECK: br i1 %CC, label %isNull, label %DoCall
+
+DoCall:         ; preds = %0
+; CHECK: DoCall:
+; CHECK: call void %FP()
+; CHECK: ret void
+        call void %FP( )
+        ret void
+
+isNull:         ; preds = %0
+; CHECK: isNull:
+; CHECK: ret void
+        ret void
+}
+
+attributes #0 = { "null-pointer-is-valid"="true" }
diff --git a/llvm/test/Transforms/GlobalOpt/storepointer-no-null-opt.ll b/llvm/test/Transforms/GlobalOpt/storepointer-no-null-opt.ll
new file mode 100644
index 00000000000..c9a63f0080d
--- /dev/null
+++ b/llvm/test/Transforms/GlobalOpt/storepointer-no-null-opt.ll
@@ -0,0 +1,27 @@
+; RUN: opt < %s -globalopt -S | FileCheck %s
+
+@G = internal global void ()* null              ; <void ()**> [#uses=2]
+; CHECK: global
+
+define internal void @Actual() {
+; CHECK-LABEL: Actual(
+        ret void
+}
+
+define void @init() {
+; CHECK-LABEL: init(
+; CHECK:  store void ()* @Actual, void ()** @G
+        store void ()* @Actual, void ()** @G
+        ret void
+}
+
+define void @doit() #0 {
+; CHECK-LABEL: doit(
+; CHECK: %FP = load void ()*, void ()** @G
+; CHECK: call void %FP()
+        %FP = load void ()*, void ()** @G         ; <void ()*> [#uses=1]
+        call void %FP( )
+        ret void
+}
+
+attributes #0 = { "null-pointer-is-valid"="true" }