From 0a9b27933a7aa84d04f133096727e94300dfc3be Mon Sep 17 00:00:00 2001
From: Tim Northover <tnorthover@apple.com>
Date: Wed, 8 Feb 2017 21:22:15 +0000
Subject: GlobalISel: expand mul-with-overflow into mul-hi on AArch64.

AArch64 has specific instructions to multiply two numbers at double the width
and produce the high part of the result. These can be used to implement LLVM's
mul.with.overflow instructions fairly simply. Helps with C++ operator new[].

llvm-svn: 294519
---
 .../test/CodeGen/AArch64/GlobalISel/legalize-mul.mir | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

(limited to 'llvm/test')

diff --git a/llvm/test/CodeGen/AArch64/GlobalISel/legalize-mul.mir b/llvm/test/CodeGen/AArch64/GlobalISel/legalize-mul.mir
index e56eef0bc4f..36726b7a30c 100644
--- a/llvm/test/CodeGen/AArch64/GlobalISel/legalize-mul.mir
+++ b/llvm/test/CodeGen/AArch64/GlobalISel/legalize-mul.mir
@@ -7,6 +7,7 @@
   entry:
     ret void
   }
+  define void @test_mul_overflow() { ret void }
 ...
 
 ---
@@ -35,3 +36,22 @@ body: |
     %5(s64) = G_ANYEXT %2
     %x0 = COPY %5
 ...
+
+
+---
+name:            test_mul_overflow
+body: |
+  bb.0:
+    liveins: %x0, %x1, %w2, %w3
+
+    %0:_(s64) = COPY %x0
+    %1:_(s64) = COPY %x1
+
+    ; CHECK-LABEL: name: test_mul_overflow
+    ; CHECK: %2(s64) = G_MUL %0, %1
+    ; CHECK: [[HI:%[0-9]+]](s64) = G_SMULH %0, %1
+    ; CHECK: [[ZERO:%[0-9]+]](s64) = G_CONSTANT i64 0
+    ; CHECK: %3(s1) = G_ICMP intpred(ne), [[HI]](s64), [[ZERO]]
+    %2:_(s64), %3:_(s1) = G_SMULO %0, %1
+
+...
-- 
cgit v1.2.3