From 3791b605f8e89887af23f54d95c202ac1d5a6101 Mon Sep 17 00:00:00 2001
From: Nikos Nikoleris <nikos.nikoleris@arm.com>
Date: Wed, 30 Oct 2019 23:45:36 +0100
Subject: [PATCH] arch-arm: Simplify AMO code generation templates

This change simplifies the isa template for the atomic memory
operation (AMO). Previously the flow had unecessary if statements that
ended up breaking build using clang, due to variables that could
seemingly be used before they were unitialized.

Change-Id: I1b46dfd5f1e90377245c4f649c08b6532b507b9c
Signed-off-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/22603
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
---
 src/arch/arm/isa/templates/mem64.isa | 48 ++++++++--------------------
 1 file changed, 14 insertions(+), 34 deletions(-)

diff --git a/src/arch/arm/isa/templates/mem64.isa b/src/arch/arm/isa/templates/mem64.isa
index e5df80155..3d0302a73 100644
--- a/src/arch/arm/isa/templates/mem64.isa
+++ b/src/arch/arm/isa/templates/mem64.isa
@@ -737,34 +737,27 @@ def template AmoOpExecute {{
                                   Trace::InstRecord *traceData) const
     {
         Addr EA;
-        Fault fault = NoFault;
 
         %(op_decl)s;
         %(op_rd)s;
         %(ea_code)s;
 
         %(usrDecl)s;
-        if (fault == NoFault) {
-            %(memacc_code)s;
-        }
 
-        %(amo_code)s
+        %(memacc_code)s;
+
+        %(amo_code)s;
         assert(amo_op);
 
-        if (fault == NoFault) {
-            fault = amoMemAtomic(xc, traceData, Mem, EA,
-                memAccessFlags, amo_op);
-        }
+        const Fault fault = amoMemAtomic(xc, traceData, Mem, EA,
+                                         memAccessFlags, amo_op);
 
         if (fault == NoFault) {
             %(postacc_code)s;
-        }
-
-        if (fault == NoFault) {
             %(op_wb)s;
         }
 
-         return fault;
+        return fault;
     }
 }};
 
@@ -773,26 +766,19 @@ def template AmoOpInitiateAcc {{
                                       Trace::InstRecord *traceData) const
     {
         Addr EA;
-        Fault fault = NoFault;
 
         %(op_src_decl)s;
         %(op_rd)s;
         %(ea_code)s;
         %(usrDecl)s;
 
-        if (fault == NoFault) {
-            %(memacc_code)s;
-        }
+        %(memacc_code)s;
 
         %(amo_code)s;
 
         assert(amo_op);
-        if (fault == NoFault) {
-            fault = initiateMemAMO(xc, traceData, EA, Mem, memAccessFlags,
-                                   amo_op);
-        }
-
-        return fault;
+        return initiateMemAMO(xc, traceData, EA, Mem, memAccessFlags,
+                              amo_op);
      }
 }};
 
@@ -800,23 +786,17 @@ def template AmoOpCompleteAcc {{
     Fault %(class_name)s::completeAcc(PacketPtr pkt, ExecContext *xc,
                                       Trace::InstRecord *traceData) const
     {
-         Fault fault = NoFault;
-
-         %(op_decl)s;
-         %(op_rd)s;
+        %(op_decl)s;
+        %(op_rd)s;
 
          // ARM instructions will not have a pkt if the predicate is false
         getMem(pkt, Mem, traceData);
 
-        if (fault == NoFault) {
-            %(postacc_code)s;
-        }
+        %(postacc_code)s;
 
-        if (fault == NoFault) {
-            %(op_wb)s;
-        }
+        %(op_wb)s;
 
-         return fault;
+        return NoFault;
     }
 
 }};
-- 
2.30.2