From: Juergen Ributzka <juergen@apple.com>
Date: Thu, 18 Sep 2014 07:04:49 +0000 (+0000)
Subject: [FastISel][AArch64] Followup commit for 218031 to handle negative offsets too.
X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=commitdiff_plain;h=4b6f00ad1816ec3dd15fc83090e970e83728dc22

[FastISel][AArch64] Followup commit for 218031 to handle negative offsets too.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218032 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/AArch64/AArch64FastISel.cpp b/lib/Target/AArch64/AArch64FastISel.cpp
index ff56209d2ff..cb0fa958a5a 100644
--- a/lib/Target/AArch64/AArch64FastISel.cpp
+++ b/lib/Target/AArch64/AArch64FastISel.cpp
@@ -917,11 +917,15 @@ bool AArch64FastISel::simplifyAddress(Address &Addr, MVT VT) {
   // Since the offset is too large for the load/store instruction get the
   // reg+offset into a register.
   if (ImmediateOffsetNeedsLowering) {
-    unsigned ResultReg = 0;
+    unsigned ResultReg;
     if (Addr.getReg()) {
       // Try to fold the immediate into the add instruction.
-      ResultReg = emitAddSub_ri(/*UseAdd=*/true, MVT::i64, Addr.getReg(),
-                                /*IsKill=*/false, Offset);
+      if (Offset < 0)
+        ResultReg = emitAddSub_ri(/*UseAdd=*/false, MVT::i64, Addr.getReg(),
+                                  /*IsKill=*/false, -Offset);
+      else
+        ResultReg = emitAddSub_ri(/*UseAdd=*/true, MVT::i64, Addr.getReg(),
+                                  /*IsKill=*/false, Offset);
       if (!ResultReg) {
         unsigned ImmReg = fastEmit_i(MVT::i64, MVT::i64, ISD::Constant, Offset);
         ResultReg = emitAddSub_rr(/*UseAdd=*/true, MVT::i64, Addr.getReg(),
diff --git a/test/CodeGen/AArch64/fast-isel-addressing-modes.ll b/test/CodeGen/AArch64/fast-isel-addressing-modes.ll
index 88a845821f2..e562a5dba05 100644
--- a/test/CodeGen/AArch64/fast-isel-addressing-modes.ll
+++ b/test/CodeGen/AArch64/fast-isel-addressing-modes.ll
@@ -130,12 +130,9 @@ define i32 @load_breg_immoff_1(i64 %a) {
 
 ; Min not-supported negative offset
 define i32 @load_breg_immoff_2(i64 %a) {
-; SDAG-LABEL: load_breg_immoff_2
-; SDAG:       sub [[REG:x[0-9]+]], x0, #257
-; SDAG-NEXT:  ldr {{w[0-9]+}}, {{\[}}[[REG]]{{\]}}
-; FAST-LABEL: load_breg_immoff_2
-; FAST:       add [[REG:x[0-9]+]], x0, {{x[0-9]+}}
-; FAST-NEXT:  ldr {{w[0-9]+}}, {{\[}}[[REG]]{{\]}}
+; CHECK-LABEL: load_breg_immoff_2
+; CHECK:       sub [[REG:x[0-9]+]], x0, #257
+; CHECK-NEXT:  ldr {{w[0-9]+}}, {{\[}}[[REG]]{{\]}}
   %1 = add i64 %a, -257
   %2 = inttoptr i64 %1 to i32*
   %3 = load i32* %2
@@ -196,12 +193,9 @@ define void @store_breg_immoff_1(i64 %a) {
 
 ; Min not-supported negative offset
 define void @store_breg_immoff_2(i64 %a) {
-; SDAG-LABEL: store_breg_immoff_2
-; SDAG:       sub [[REG:x[0-9]+]], x0, #257
-; SDAG-NEXT:  str wzr, {{\[}}[[REG]]{{\]}}
-; FAST-LABEL: store_breg_immoff_2
-; FAST:       add [[REG:x[0-9]+]], x0, {{x[0-9]+}}
-; FAST-NEXT:  str wzr, {{\[}}[[REG]]{{\]}}
+; CHECK-LABEL: store_breg_immoff_2
+; CHECK:       sub [[REG:x[0-9]+]], x0, #257
+; CHECK-NEXT:  str wzr, {{\[}}[[REG]]{{\]}}
   %1 = add i64 %a, -257
   %2 = inttoptr i64 %1 to i32*
   store i32 0, i32* %2