From 291cd09645a3bbd5dfd7ccf1039b783a1a2fa54c Mon Sep 17 00:00:00 2001
From: Tim Northover <tnorthover@apple.com>
Date: Thu, 8 May 2014 10:30:56 +0000
Subject: [PATCH] ARM64: make sure FastISel emits SSA MachineInstrs

We need to use a temporary register for a 2-step operation like REM.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208297 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/ARM64/ARM64FastISel.cpp  |  7 ++++---
 test/CodeGen/ARM64/fast-isel-rem.ll | 27 +++++++++++++++++++--------
 2 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/lib/Target/ARM64/ARM64FastISel.cpp b/lib/Target/ARM64/ARM64FastISel.cpp
index 78cde1c22c9..0d4001ebf67 100644
--- a/lib/Target/ARM64/ARM64FastISel.cpp
+++ b/lib/Target/ARM64/ARM64FastISel.cpp
@@ -1849,14 +1849,15 @@ bool ARM64FastISel::SelectRem(const Instruction *I, unsigned ISDOpcode) {
   if (!Src1Reg)
     return false;
 
-  unsigned ResultReg = createResultReg(TLI.getRegClassFor(DestVT));
-  BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(DivOpc), ResultReg)
+  unsigned QuotReg = createResultReg(TLI.getRegClassFor(DestVT));
+  BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(DivOpc), QuotReg)
       .addReg(Src0Reg)
       .addReg(Src1Reg);
   // The remainder is computed as numerator - (quotient * denominator) using the
   // MSUB instruction.
+  unsigned ResultReg = createResultReg(TLI.getRegClassFor(DestVT));
   BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(MSubOpc), ResultReg)
-      .addReg(ResultReg)
+      .addReg(QuotReg)
       .addReg(Src1Reg)
       .addReg(Src0Reg);
   UpdateValueMap(I, ResultReg);
diff --git a/test/CodeGen/ARM64/fast-isel-rem.ll b/test/CodeGen/ARM64/fast-isel-rem.ll
index 0c68401f5c5..d5bdbaae9e7 100644
--- a/test/CodeGen/ARM64/fast-isel-rem.ll
+++ b/test/CodeGen/ARM64/fast-isel-rem.ll
@@ -1,33 +1,44 @@
 ; RUN: llc < %s -O0 -fast-isel-abort -mtriple=arm64-apple-darwin | FileCheck %s
+; RUN: llc %s -O0 -fast-isel-abort -mtriple=arm64-apple-darwin -print-machineinstrs=expand-isel-pseudos -o /dev/null 2> %t
+; RUN: FileCheck %s < %t --check-prefix=CHECK-SSA
+; REQUIRES: asserts
+
+; CHECK-SSA-LABEL: Machine code for function t1
+
+; CHECK-SSA: [[QUOTREG:%vreg[0-9]+]]<def> = SDIVWr
+; CHECK-SSA-NOT: [[QUOTREG]]<def> =
+; CHECK-SSA: {{%vreg[0-9]+}}<def> = MSUBWrrr [[QUOTREG]]
+
+; CHECK-SSA-LABEL: Machine code for function t2
 
 define i32 @t1(i32 %a, i32 %b) {
 ; CHECK: @t1
-; CHECK: sdiv w2, w0, w1
-; CHECK: msub w2, w2, w1, w0
+; CHECK: sdiv [[TMP:w[0-9]+]], w0, w1
+; CHECK: msub w0, [[TMP]], w1, w0
   %1 = srem i32 %a, %b
   ret i32 %1
 }
 
 define i64 @t2(i64 %a, i64 %b) {
 ; CHECK: @t2
-; CHECK: sdiv x2, x0, x1
-; CHECK: msub x2, x2, x1, x0
+; CHECK: sdiv [[TMP:x[0-9]+]], x0, x1
+; CHECK: msub x0, [[TMP]], x1, x0
   %1 = srem i64 %a, %b
   ret i64 %1
 }
 
 define i32 @t3(i32 %a, i32 %b) {
 ; CHECK: @t3
-; CHECK: udiv w2, w0, w1
-; CHECK: msub w2, w2, w1, w0
+; CHECK: udiv [[TMP:w[0-9]+]], w0, w1
+; CHECK: msub w0, [[TMP]], w1, w0
   %1 = urem i32 %a, %b
   ret i32 %1
 }
 
 define i64 @t4(i64 %a, i64 %b) {
 ; CHECK: @t4
-; CHECK: udiv x2, x0, x1
-; CHECK: msub x2, x2, x1, x0
+; CHECK: udiv [[TMP:x[0-9]+]], x0, x1
+; CHECK: msub x0, [[TMP]], x1, x0
   %1 = urem i64 %a, %b
   ret i64 %1
 }