From: Vasileios Kalintiris <Vasileios.Kalintiris@imgtec.com>
Date: Sat, 18 Jun 2016 15:39:43 +0000 (+0000)
Subject: [mips] Emit a JALR with $rd equal to $zero, instead of a JR in MIPS32R6.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=76bbc90afa0be2cb0a0cdca190271b9024a66351;p=llvm

[mips] Emit a JALR with $rd equal to $zero, instead of a JR in MIPS32R6.

Summary:
JR is an alias of JALR with $rd=0 in the R6 ISA. Also, this fixes recursive
builds in MIPS32R6.

Reviewers: dsanders, sdardis

Subscribers: jfb, dschuff, dsanders, sdardis, llvm-commits

Differential Revision: http://reviews.llvm.org/D21370

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@273085 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/Mips/MipsLongBranch.cpp b/lib/Target/Mips/MipsLongBranch.cpp
index 9640408e1cc..8a48d863c8b 100644
--- a/lib/Target/Mips/MipsLongBranch.cpp
+++ b/lib/Target/Mips/MipsLongBranch.cpp
@@ -335,23 +335,26 @@ void MipsLongBranch::expandToLongBranch(MBBInfo &I) {
       BuildMI(*BalTgtMBB, Pos, DL, TII->get(Mips::LW), Mips::RA)
         .addReg(Mips::SP).addImm(0);
 
-      if (!Subtarget.isTargetNaCl()) {
-        MIBundleBuilder(*BalTgtMBB, Pos)
-          .append(BuildMI(*MF, DL, TII->get(Mips::JR)).addReg(Mips::AT))
-          .append(BuildMI(*MF, DL, TII->get(Mips::ADDiu), Mips::SP)
-                  .addReg(Mips::SP).addImm(8));
-      } else {
-        // In NaCl, modifying the sp is not allowed in branch delay slot.
+      // In NaCl, modifying the sp is not allowed in branch delay slot.
+      if (Subtarget.isTargetNaCl())
         BuildMI(*BalTgtMBB, Pos, DL, TII->get(Mips::ADDiu), Mips::SP)
           .addReg(Mips::SP).addImm(8);
 
-        MIBundleBuilder(*BalTgtMBB, Pos)
-          .append(BuildMI(*MF, DL, TII->get(Mips::JR)).addReg(Mips::AT))
-          .append(BuildMI(*MF, DL, TII->get(Mips::NOP)));
+      if (Subtarget.hasMips32r6())
+        BuildMI(*BalTgtMBB, Pos, DL, TII->get(Mips::JALR))
+          .addReg(Mips::ZERO).addReg(Mips::AT);
+      else
+        BuildMI(*BalTgtMBB, Pos, DL, TII->get(Mips::JR)).addReg(Mips::AT);
 
+      if (Subtarget.isTargetNaCl()) {
+        BuildMI(*BalTgtMBB, Pos, DL, TII->get(Mips::NOP));
         // Bundle-align the target of indirect branch JR.
         TgtMBB->setAlignment(MIPS_NACL_BUNDLE_ALIGN);
-      }
+      } else
+        BuildMI(*BalTgtMBB, Pos, DL, TII->get(Mips::ADDiu), Mips::SP)
+          .addReg(Mips::SP).addImm(8);
+
+      BalTgtMBB->rbegin()->bundleWithPred();
     } else {
       // $longbr:
       //  daddiu $sp, $sp, -16
@@ -410,10 +413,15 @@ void MipsLongBranch::expandToLongBranch(MBBInfo &I) {
       BuildMI(*BalTgtMBB, Pos, DL, TII->get(Mips::LD), Mips::RA_64)
         .addReg(Mips::SP_64).addImm(0);
 
-      MIBundleBuilder(*BalTgtMBB, Pos)
-        .append(BuildMI(*MF, DL, TII->get(Mips::JR64)).addReg(Mips::AT_64))
-        .append(BuildMI(*MF, DL, TII->get(Mips::DADDiu), Mips::SP_64)
-                .addReg(Mips::SP_64).addImm(16));
+      if (Subtarget.hasMips64r6())
+        BuildMI(*BalTgtMBB, Pos, DL, TII->get(Mips::JALR64))
+          .addReg(Mips::ZERO_64).addReg(Mips::AT_64);
+      else
+        BuildMI(*BalTgtMBB, Pos, DL, TII->get(Mips::JR64)).addReg(Mips::AT_64);
+
+      BuildMI(*BalTgtMBB, Pos, DL, TII->get(Mips::DADDiu), Mips::SP_64)
+        .addReg(Mips::SP_64).addImm(16);
+      BalTgtMBB->rbegin()->bundleWithPred();
     }
 
     assert(LongBrMBB->size() + BalTgtMBB->size() == LongBranchSeqSize);
diff --git a/test/CodeGen/Mips/longbranch.ll b/test/CodeGen/Mips/longbranch.ll
index d2eabf87ce7..06eda11e788 100644
--- a/test/CodeGen/Mips/longbranch.ll
+++ b/test/CodeGen/Mips/longbranch.ll
@@ -1,10 +1,14 @@
 ; RUN: llc -march=mipsel -relocation-model=pic < %s | FileCheck %s
 ; RUN: llc -march=mipsel -force-mips-long-branch -O3 -relocation-model=pic < %s \
 ; RUN:   | FileCheck %s -check-prefix=O32
+; RUN: llc -march=mipsel -mcpu=mips32r6 -force-mips-long-branch -O3 \
+; RUN:   -relocation-model=pic -asm-show-inst < %s | FileCheck %s -check-prefix=O32-R6
 ; RUN: llc -march=mips64el -mcpu=mips4 -target-abi=n64 -force-mips-long-branch -O3 -relocation-model=pic \
 ; RUN:   < %s | FileCheck %s -check-prefix=N64
 ; RUN: llc -march=mips64el -mcpu=mips64 -target-abi=n64 -force-mips-long-branch -O3 -relocation-model=pic \
 ; RUN:   < %s | FileCheck %s -check-prefix=N64
+; RUN: llc -march=mips64el -mcpu=mips64r6 -target-abi=n64 -force-mips-long-branch -O3 \
+; RUN:   -relocation-model=pic -asm-show-inst < %s | FileCheck %s -check-prefix=N64-R6
 ; RUN: llc -march=mipsel -mcpu=mips32r2 -mattr=micromips \
 ; RUN:   -force-mips-long-branch -O3 -relocation-model=pic < %s | FileCheck %s -check-prefix=MICROMIPS
 ; RUN: llc -mtriple=mipsel-none-nacl -force-mips-long-branch -O3 -relocation-model=pic < %s \
@@ -72,6 +76,10 @@ end:
 ; O32:        jr      $ra
 ; O32:        nop
 
+; In MIPS32R6 JR is an alias to JALR with $rd=0. As everything else remains the
+; same with the O32 prefix, we use -asm-show-inst in order to make sure that
+; the opcode of the MachineInst is a JALR.
+; O32-R6:     JALR
 
 ; Check the MIPS64 version.
 
@@ -101,6 +109,11 @@ end:
 ; N64:        jr      $ra
 ; N64:        nop
 
+; In MIPS64R6 JR is an alias to JALR with $rd=0. As everything else remains the
+; same with the N64 prefix, we use -asm-show-inst in order to make sure that
+; the opcode of the MachineInst is a JALR.
+; N64-R6:     JALR64
+
 
 ; Check the microMIPS version.