From 5802ab56b6435e8ea39616d04751b32b9996bfb7 Mon Sep 17 00:00:00 2001
From: Mike Pall <mike>
Date: Mon, 29 Apr 2019 17:38:05 +0200
Subject: [PATCH 1/2] ARM: Fix condition code check fusion.

Reported by Qingjun Wei.
---
 src/lj_asm_arm.h | 28 +++++++++++++++-------------
 1 file changed, 15 insertions(+), 13 deletions(-)

diff --git a/src/lj_asm_arm.h b/src/lj_asm_arm.h
index 961f7e39..8e0ebd7a 100644
--- a/src/lj_asm_arm.h
+++ b/src/lj_asm_arm.h
@@ -1449,19 +1449,10 @@ static void asm_intop(ASMState *as, IRIns *ir, ARMIns ai)
   emit_dn(as, ai^m, dest, left);
 }
 
-static void asm_intop_s(ASMState *as, IRIns *ir, ARMIns ai)
+/* Try to drop cmp r, #0. */
+static ARMIns asm_drop_cmp0(ASMState *as, ARMIns ai)
 {
-  if (as->flagmcp == as->mcp) {  /* Drop cmp r, #0. */
-    as->flagmcp = NULL;
-    as->mcp++;
-    ai |= ARMI_S;
-  }
-  asm_intop(as, ir, ai);
-}
-
-static void asm_bitop(ASMState *as, IRIns *ir, ARMIns ai)
-{
-  if (as->flagmcp == as->mcp) {  /* Try to drop cmp r, #0. */
+  if (as->flagmcp == as->mcp) {
     uint32_t cc = (as->mcp[1] >> 28);
     as->flagmcp = NULL;
     if (cc <= CC_NE) {
@@ -1473,8 +1464,19 @@ static void asm_bitop(ASMState *as, IRIns *ir, ARMIns ai)
     } else if (cc == CC_LT) {
       *++as->mcp ^= ((CC_LT^CC_MI) << 28);
       ai |= ARMI_S;
-    }  /* else: other conds don't work with bit ops. */
+    }  /* else: other conds don't work in general. */
   }
+  return ai;
+}
+
+static void asm_intop_s(ASMState *as, IRIns *ir, ARMIns ai)
+{
+  asm_intop(as, ir, asm_drop_cmp0(as, ai));
+}
+
+static void asm_bitop(ASMState *as, IRIns *ir, ARMIns ai)
+{
+  ai = asm_drop_cmp0(as, ai);
   if (ir->op2 == 0) {
     Reg dest = ra_dest(as, ir, RSET_GPR);
     uint32_t m = asm_fuseopm(as, ai, ir->op1, RSET_GPR);

From 9bd5a722bee2ee2c5b159a89937778b81be49915 Mon Sep 17 00:00:00 2001
From: Mike Pall <mike>
Date: Mon, 29 Apr 2019 18:02:50 +0200
Subject: [PATCH 2/2] ARM: Fix GCC 7 -Wimplicit-fallthrough warnings.

---
 src/lj_asm.c     | 2 +-
 src/lj_asm_arm.h | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/lj_asm.c b/src/lj_asm.c
index dd7186f6..8ce7bbd6 100644
--- a/src/lj_asm.c
+++ b/src/lj_asm.c
@@ -1719,8 +1719,8 @@ static void asm_setup_regsp(ASMState *as)
 #if LJ_SOFTFP
     case IR_MIN: case IR_MAX:
       if ((ir+1)->o != IR_HIOP) break;
-      /* fallthrough */
 #endif
+    /* fallthrough */
     /* C calls evict all scratch regs and return results in RID_RET. */
     case IR_SNEW: case IR_XSNEW: case IR_NEWREF:
       if (REGARG_NUMGPR < 3 && as->evenspill < 3)
diff --git a/src/lj_asm_arm.h b/src/lj_asm_arm.h
index 8e0ebd7a..ccd20545 100644
--- a/src/lj_asm_arm.h
+++ b/src/lj_asm_arm.h
@@ -1046,7 +1046,7 @@ static ARMIns asm_fxloadins(IRIns *ir)
   case IRT_I16: return ARMI_LDRSH;
   case IRT_U16: return ARMI_LDRH;
   case IRT_NUM: lua_assert(!LJ_SOFTFP); return ARMI_VLDR_D;
-  case IRT_FLOAT: if (!LJ_SOFTFP) return ARMI_VLDR_S;
+  case IRT_FLOAT: if (!LJ_SOFTFP) return ARMI_VLDR_S;  /* fallthrough */
   default: return ARMI_LDR;
   }
 }
@@ -1057,7 +1057,7 @@ static ARMIns asm_fxstoreins(IRIns *ir)
   case IRT_I8: case IRT_U8: return ARMI_STRB;
   case IRT_I16: case IRT_U16: return ARMI_STRH;
   case IRT_NUM: lua_assert(!LJ_SOFTFP); return ARMI_VSTR_D;
-  case IRT_FLOAT: if (!LJ_SOFTFP) return ARMI_VSTR_S;
+  case IRT_FLOAT: if (!LJ_SOFTFP) return ARMI_VSTR_S;  /* fallthrough */
   default: return ARMI_STR;
   }
 }