From 7773c58458157a45df8252322da8a840dc12bfdd Mon Sep 17 00:00:00 2001
From: Krzysztof Parzyszek <kparzysz@codeaurora.org>
Date: Thu, 4 Aug 2016 14:17:16 +0000
Subject: [PATCH] [Hexagon] Clear kill flags from modified registers in
 peephole optimizer

llvm-svn: 277727
---
 llvm/lib/Target/Hexagon/HexagonPeephole.cpp      |  5 ++++-
 llvm/test/CodeGen/Hexagon/peephole-kill-flags.ll | 27 ++++++++++++++++++++++++
 2 files changed, 31 insertions(+), 1 deletion(-)
 create mode 100644 llvm/test/CodeGen/Hexagon/peephole-kill-flags.ll

diff --git a/llvm/lib/Target/Hexagon/HexagonPeephole.cpp b/llvm/lib/Target/Hexagon/HexagonPeephole.cpp
index b064dec..8d1ddeb 100644
--- a/llvm/lib/Target/Hexagon/HexagonPeephole.cpp
+++ b/llvm/lib/Target/Hexagon/HexagonPeephole.cpp
@@ -250,6 +250,7 @@ bool HexagonPeephole::runOnMachineFunction(MachineFunction &MF) {
               if (unsigned PeepholeSrc = PeepholeMap.lookup(Reg0)) {
                 // Change the 1st operand and, flip the opcode.
                 MI.getOperand(0).setReg(PeepholeSrc);
+                MRI->clearKillFlags(PeepholeSrc);
                 int NewOp = QII->getInvertedPredicatedOpcode(MI.getOpcode());
                 MI.setDesc(QII->get(NewOp));
                 Done = true;
@@ -280,6 +281,7 @@ bool HexagonPeephole::runOnMachineFunction(MachineFunction &MF) {
             unsigned PSrc = MI.getOperand(PR).getReg();
             if (unsigned POrig = PeepholeMap.lookup(PSrc)) {
               MI.getOperand(PR).setReg(POrig);
+              MRI->clearKillFlags(POrig);
               MI.setDesc(QII->get(NewOp));
               // Swap operands S1 and S2.
               MachineOperand Op1 = MI.getOperand(S1);
@@ -304,6 +306,7 @@ void HexagonPeephole::ChangeOpInto(MachineOperand &Dst, MachineOperand &Src) {
       if (Src.isReg()) {
         Dst.setReg(Src.getReg());
         Dst.setSubReg(Src.getSubReg());
+        MRI->clearKillFlags(Src.getReg());
       } else if (Src.isImm()) {
         Dst.ChangeToImmediate(Src.getImm());
       } else {
@@ -316,7 +319,7 @@ void HexagonPeephole::ChangeOpInto(MachineOperand &Dst, MachineOperand &Src) {
         Dst.setImm(Src.getImm());
       } else if (Src.isReg()) {
         Dst.ChangeToRegister(Src.getReg(), Src.isDef(), Src.isImplicit(),
-                             Src.isKill(), Src.isDead(), Src.isUndef(),
+                             false, Src.isDead(), Src.isUndef(),
                              Src.isDebug());
         Dst.setSubReg(Src.getSubReg());
       } else {
diff --git a/llvm/test/CodeGen/Hexagon/peephole-kill-flags.ll b/llvm/test/CodeGen/Hexagon/peephole-kill-flags.ll
new file mode 100644
index 0000000..03de1532
--- /dev/null
+++ b/llvm/test/CodeGen/Hexagon/peephole-kill-flags.ll
@@ -0,0 +1,27 @@
+; RUN: llc -march=hexagon -verify-machineinstrs < %s | FileCheck %s
+; CHECK: memw
+
+; Check that the testcase compiles without errors.
+
+target triple = "hexagon"
+
+; Function Attrs: nounwind
+define void @fred() #0 {
+entry:
+  br label %for.cond
+
+for.cond:                                         ; preds = %entry
+  %0 = load i32, i32* undef, align 4
+  %mul = mul nsw i32 2, %0
+  %cmp = icmp slt i32 undef, %mul
+  br i1 %cmp, label %for.body, label %for.end13
+
+for.body:                                         ; preds = %for.cond
+  unreachable
+
+for.end13:                                        ; preds = %for.cond
+  ret void
+}
+
+attributes #0 = { nounwind "target-cpu"="hexagonv60" "target-features"="+hvx,-hvx-double" }
+
-- 
2.7.4