From 4b476488baeb5216a46e51bcdff0c8de366260a5 Mon Sep 17 00:00:00 2001
From: John Brawn <john.brawn@arm.com>
Date: Mon, 27 Nov 2017 11:29:15 +0000
Subject: [CGP] Fix handling of null pointer values in optimizeMemoryInst

The current way that trivial addressing modes are detected incorrectly thinks
that null pointers are non-trivial, leading to an infinite loop where we keep
duplicating the same select. Fix this by aware of null when deciding if an
addressing mode is trivial.

Differential Revision: https://reviews.llvm.org/D40447

llvm-svn: 319019
---
 .../Transforms/CodeGenPrepare/ARM/sink-addrmode.ll | 52 ++++++++++++++++++++++
 1 file changed, 52 insertions(+)

(limited to 'llvm/test')

diff --git a/llvm/test/Transforms/CodeGenPrepare/ARM/sink-addrmode.ll b/llvm/test/Transforms/CodeGenPrepare/ARM/sink-addrmode.ll
index 0be9c556f93..a26edb19da0 100644
--- a/llvm/test/Transforms/CodeGenPrepare/ARM/sink-addrmode.ll
+++ b/llvm/test/Transforms/CodeGenPrepare/ARM/sink-addrmode.ll
@@ -366,3 +366,55 @@ entey:
   store i32 %value, i32* %select, align 4
   ret void
 }
+
+; Same for a select between a value and global variable
+; CHECK-LABEL: @test_select_trivial_ptr_gv
+; CHECK: select i1 %cmp, i32* %ptr, i32* @gv2
+define void @test_select_trivial_ptr_gv(i32* %ptr, i32 %value) {
+entry:
+  %cmp = icmp sgt i32 %value, 0
+  %select = select i1 %cmp, i32* %ptr, i32* @gv2
+  store i32 %value, i32* %select, align 4
+  ret void
+}
+
+; Same for a select between a global variable and null, though the test needs to
+; be a little more complicated to avoid dereferencing a potential null pointer
+; CHECK-LABEL: @test_select_trivial_gv_null
+; CHECK: select i1 %cmp.i, i32* @gv1, i32* null
+define void @test_select_trivial_gv_null(){
+entry:
+  %gv1_val = load i32, i32* @gv1, align 4
+  %cmp.i = icmp eq i32 %gv1_val, 0
+  %spec.select.i = select i1 %cmp.i, i32* @gv1, i32* null
+  br i1 %cmp.i, label %if.then, label %if.end
+
+if.then:
+  %val = load i32, i32* %spec.select.i, align 4
+  %inc = add nsw i32 %val, 1
+  store i32 %inc, i32* %spec.select.i, align 4
+  br label %if.end
+
+if.end:
+  ret void
+}
+
+; Same for a select between a value and null
+; CHECK-LABEL: @test_select_trivial_ptr_null
+; CHECK: select i1 %cmp.i, i32* %ptr, i32* null
+define void @test_select_trivial_ptr_null(i32* %ptr){
+entry:
+  %gv1_val = load i32, i32* %ptr, align 4
+  %cmp.i = icmp eq i32 %gv1_val, 0
+  %spec.select.i = select i1 %cmp.i, i32* %ptr, i32* null
+  br i1 %cmp.i, label %if.then, label %if.end
+
+if.then:
+  %val = load i32, i32* %spec.select.i, align 4
+  %inc = add nsw i32 %val, 1
+  store i32 %inc, i32* %spec.select.i, align 4
+  br label %if.end
+
+if.end:
+  ret void
+}
-- 
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