Hexagon (target/hexagon) Only use branch_taken when packet has multi cof

When a packet has more than one change-of-flow instruction, only the first
one to branch is considered.  We use the branch_taken variable to keep
track of this.

However, when there is a single cof instruction, we don't need the same
amount of bookkeeping.

We add the pkt_has_multi_cof member to the Packet structure, and pass this
information to the needed functions.

When there is a generated helper function with cof, the generator will
pass this pkt_has_multi_cof as a runtime value.

Acked-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Taylor Simpson <tsimpson@quicinc.com>
Message-Id: <20221108162906.3166-5-tsimpson@quicinc.com>

1 files changed, 15 insertions, 9 deletions

diff --git a/target/hexagon/op_helper.c b/target/hexagon/op_helper.c
index 085afc3..84391e2 100644
--- a/target/hexagon/op_helper.c
+++ b/target/hexagon/op_helper.c
@@ -104,20 +104,26 @@ static void log_store64(CPUHexagonState *env, target_ulong addr,
     env->mem_log_stores[slot].data64 = val;
 }
 
-static void write_new_pc(CPUHexagonState *env, target_ulong addr)
+static void write_new_pc(CPUHexagonState *env, bool pkt_has_multi_cof,
+                         target_ulong addr)
 {
     HEX_DEBUG_LOG("write_new_pc(0x" TARGET_FMT_lx ")\n", addr);
 
-    /*
-     * If more than one branch is taken in a packet, only the first one
-     * is actually done.
-     */
-    if (env->branch_taken) {
-        HEX_DEBUG_LOG("INFO: multiple branches taken in same packet, "
-                      "ignoring the second one\n");
+    if (pkt_has_multi_cof) {
+        /*
+         * If more than one branch is taken in a packet, only the first one
+         * is actually done.
+         */
+        if (env->branch_taken) {
+            HEX_DEBUG_LOG("INFO: multiple branches taken in same packet, "
+                          "ignoring the second one\n");
+        } else {
+            fCHECK_PCALIGN(addr);
+            env->next_PC = addr;
+            env->branch_taken = 1;
+        }
     } else {
         fCHECK_PCALIGN(addr);
-        env->branch_taken = 1;
         env->next_PC = addr;
     }
 }