From a08b54b29557ff687b3c40c6800833a4dc949be5 Mon Sep 17 00:00:00 2001
From: Stephan Hadinger <stephan.hadinger@gmail.com>
Date: Mon, 15 Nov 2021 19:14:35 +0100
Subject: [PATCH] Fix Berry compound assignment

---
 lib/libesp32/Berry/src/be_code.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/lib/libesp32/Berry/src/be_code.c b/lib/libesp32/Berry/src/be_code.c
index 6a332bb07..3fac0bbcd 100644
--- a/lib/libesp32/Berry/src/be_code.c
+++ b/lib/libesp32/Berry/src/be_code.c
@@ -335,12 +335,15 @@ static void free_suffix(bfuncinfo *finfo, bexpdesc *e)
     }
 }
 
-static int suffix_destreg(bfuncinfo *finfo, bexpdesc *e1, int dst)
+static int suffix_destreg(bfuncinfo *finfo, bexpdesc *e1, int dst, bbool no_reg_reuse)
 {
     int cand_dst = dst;  /* candidate for new dst */
     int nlocal = be_list_count(finfo->local);
     int reg1 = (e1->v.ss.tt == ETREG) ? e1->v.ss.obj : -1;  /* check if obj is ETREG or -1 */
     int reg2 = (!isK(e1->v.ss.idx) && e1->v.ss.idx >= nlocal) ? e1->v.ss.idx : -1;  /* check if idx is ETREG or -1 */
+    if (no_reg_reuse) {  /* if no_reg_reuse flag, then don't reuse any register, this is useful for compound assignments */
+        reg1 = reg2 = -1;
+    }
 
     if (reg1 >= 0 && reg2 >= 0) {
         /* both are ETREG, we keep the lowest and discard the other */
@@ -364,9 +367,9 @@ static int suffix_destreg(bfuncinfo *finfo, bexpdesc *e1, int dst)
     return dst;
 }
 
-static int code_suffix(bfuncinfo *finfo, bopcode op, bexpdesc *e, int dst)
+static int code_suffix(bfuncinfo *finfo, bopcode op, bexpdesc *e, int dst, bbool no_reg_reuse)
 {
-    dst = suffix_destreg(finfo, e, dst);
+    dst = suffix_destreg(finfo, e, dst, no_reg_reuse);
     if (dst > finfo->freereg) {
         dst = finfo->freereg;
     }
@@ -400,6 +403,7 @@ static bbool constint(bfuncinfo *finfo, bint i)
 /* At exit, If dst is `freereg`, the register is allocated */
 static int var2reg(bfuncinfo *finfo, bexpdesc *e, int dst)
 {
+    bbool no_reg_reuse = (dst >= 0);  /* if dst reg is explicitly specified, do not optimize register allocation */
     if (dst < 0) {  /* if unspecified, allocate a new register if needed */
         dst = finfo->freereg;
     }
@@ -434,10 +438,10 @@ static int var2reg(bfuncinfo *finfo, bexpdesc *e, int dst)
         codeABx(finfo, OP_GETUPV, dst, e->v.idx);
         break;
     case ETMEMBER:
-        dst = code_suffix(finfo, OP_GETMBR, e, dst);
+        dst = code_suffix(finfo, OP_GETMBR, e, dst, no_reg_reuse);
         break;
     case ETINDEX:
-        dst = code_suffix(finfo, OP_GETIDX, e, dst);
+        dst = code_suffix(finfo, OP_GETIDX, e, dst, no_reg_reuse);
         break;
     case ETLOCAL: case ETREG: case ETCONST:
         return e->v.idx;
@@ -479,6 +483,7 @@ static int exp2reg(bfuncinfo *finfo, bexpdesc *e, int dst)
 /* Returns the destination register, guaranteed to be ETREG */
 static int codedestreg(bfuncinfo *finfo, bexpdesc *e1, bexpdesc *e2, int dst)
 {
+    if (dst < 0) { dst = finfo->freereg; }
     int cand_dst = dst;
     int con1 = e1->type == ETREG, con2 = e2->type == ETREG;
 
@@ -506,7 +511,6 @@ static int codedestreg(bfuncinfo *finfo, bexpdesc *e1, bexpdesc *e2, int dst)
 /* On exit, e1 is guaranteed to be ETREG, which may have been allocated */
 static void binaryexp(bfuncinfo *finfo, bopcode op, bexpdesc *e1, bexpdesc *e2, int dst)
 {
-    if (dst < 0) { dst = finfo->freereg; }
     int src1 = exp2reg(finfo, e1, dst);  /* potentially force the target for src1 reg */
     int src2 = exp2anyreg(finfo, e2);
     dst = codedestreg(finfo, e1, e2, dst);
@@ -720,7 +724,7 @@ int be_code_getmethod(bfuncinfo *finfo, bexpdesc *e)
 {
     int dst = finfo->freereg;
     be_assert(e->type == ETMEMBER);
-    dst = code_suffix(finfo, OP_GETMET, e, dst);
+    dst = code_suffix(finfo, OP_GETMET, e, dst, bfalse);
     /* method [object] args */
     be_code_allocregs(finfo, dst == finfo->freereg ? 2 : 1);
     return dst;