From e1fbc7e8ba9d122db73e505c52221a002817df36 Mon Sep 17 00:00:00 2001
From: Colin LeMahieu <colinl@codeaurora.org>
Date: Fri, 13 Nov 2015 01:12:25 +0000
Subject: [PATCH] [Hexagon] Adding relaxation functionality to backend and
 test.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252989 91177308-0d34-0410-b5e6-96231b3b80d8
---
 .../MCTargetDesc/HexagonAsmBackend.cpp        | 34 +++++++++++++++++--
 test/MC/Hexagon/jumpdoublepound.s             | 13 +++++++
 test/MC/Hexagon/two_ext.s                     | 12 +++++++
 3 files changed, 56 insertions(+), 3 deletions(-)
 create mode 100644 test/MC/Hexagon/jumpdoublepound.s
 create mode 100644 test/MC/Hexagon/two_ext.s

diff --git a/lib/Target/Hexagon/MCTargetDesc/HexagonAsmBackend.cpp b/lib/Target/Hexagon/MCTargetDesc/HexagonAsmBackend.cpp
index 99ea2fabf86..dae0654ef48 100644
--- a/lib/Target/Hexagon/MCTargetDesc/HexagonAsmBackend.cpp
+++ b/lib/Target/Hexagon/MCTargetDesc/HexagonAsmBackend.cpp
@@ -276,9 +276,37 @@ public:
     llvm_unreachable("Handled by fixupNeedsRelaxationAdvanced");
   }
 
-  void relaxInstruction(MCInst const & /*Inst*/,
-                        MCInst & /*Res*/) const override {
-    llvm_unreachable("relaxInstruction() unimplemented");
+  void relaxInstruction(MCInst const & Inst,
+                        MCInst & Res) const override {
+    assert(HexagonMCInstrInfo::isBundle(Inst) &&
+           "Hexagon relaxInstruction only works on bundles");
+
+    Res.setOpcode(Hexagon::BUNDLE);
+    Res.addOperand(MCOperand::createImm(0));
+    // Copy the results into the bundle.
+    bool Update = false;
+    for (auto &I : HexagonMCInstrInfo::bundleInstructions(Inst)) {
+      MCInst &CrntHMI = const_cast<MCInst &>(*I.getInst());
+
+      // if immediate extender needed, add it in
+      if (*RelaxTarget == &CrntHMI) {
+        Update = true;
+        assert((HexagonMCInstrInfo::bundleSize(Res) < HEXAGON_PACKET_SIZE) &&
+               "No room to insert extender for relaxation");
+
+        MCInst *HMIx =
+            new MCInst(HexagonMCInstrInfo::deriveExtender(
+                *MCII, CrntHMI,
+                HexagonMCInstrInfo::getExtendableOperand(*MCII, CrntHMI)));
+
+        Res.addOperand(MCOperand::createInst(HMIx));
+        *RelaxTarget = nullptr;
+      }
+      // now copy over the original instruction(the one we may have extended)
+      Res.addOperand(MCOperand::createInst(I.getInst()));
+    }
+    (void)Update;
+    assert(Update && "Didn't find relaxation target");
   }
 
   bool writeNopData(uint64_t Count,
diff --git a/test/MC/Hexagon/jumpdoublepound.s b/test/MC/Hexagon/jumpdoublepound.s
new file mode 100644
index 00000000000..6b829360a90
--- /dev/null
+++ b/test/MC/Hexagon/jumpdoublepound.s
@@ -0,0 +1,13 @@
+# RUN: llvm-mc -triple=hexagon -filetype=obj %s -o - | llvm-objdump -d - | FileCheck %s
+
+# Verify that jump encodes correctly
+
+
+mylabel:
+# CHECK: if (p0) jump
+if (p0) jump ##mylabel
+
+# CHECK: if (cmp.gtu(r5.new, r4)) jump:t
+{ r5 = r4
+  if (cmp.gtu(r5.new, r4)) jump:t ##mylabel }
+
diff --git a/test/MC/Hexagon/two_ext.s b/test/MC/Hexagon/two_ext.s
new file mode 100644
index 00000000000..c55bcc8cd9f
--- /dev/null
+++ b/test/MC/Hexagon/two_ext.s
@@ -0,0 +1,12 @@
+# RUN: llvm-mc -triple=hexagon -filetype=obj %s | llvm-objdump -d - | FileCheck %s
+
+# verify two extenders generated during relaxation
+{
+  if (p1) call foo_a
+  if (!p1) call foo_b
+}
+# CHECK: 00004000 { immext(#0)
+# CHECK: 5d004100   if (p1) call 0x0
+# CHECK: 00004000   immext(#0)
+# CHECK: 5d20c100   if (!p1) call 0x0 }
+
-- 
2.34.1