test related to issue #1652, shows regression broken by #1231 and the

case that #1231 improved.

test/val/bug1652-optimizer.c

@@ -0,0 +1,122 @@
+
+/* #1652 - Regression in code optimization */
+
+#include <stdlib.h>
+
+/* better before pr#1231
+
+before:
+
+        jsr     pusha
+        ldy     #$01
+        ldx     #$00
+        lda     (sp),y
+        beq     L0005
+        lda     (sp,x)
+        beq     L0005
+        txa
+        jmp     incsp2          ; <--
+L0005:  tya
+        jmp     incsp2
+
+after:
+
+        jsr     pusha
+        ldy     #$01
+        ldx     #$00
+        lda     (sp),y
+        beq     L0004
+        lda     (sp,x)
+        beq     L0004
+        txa
+        jmp     L0001            ; <--
+L0004:  tya
+L0001:  jmp     incsp2
+
+*/
+
+int foo(unsigned char bar, unsigned char baz)
+{
+    return (bar == 0 || baz == 0);
+}
+
+/* worse before pr#1231
+
+before:
+;
+; y = 1;
+;
+    lda     #$01
+    sta     _y
+;
+; (*tablePtr)[y][x] = 83;
+;
+    ldx     #$00
+    lda     _y
+    jsr     aslax2
+    clc
+    adc     _tablePtr
+    pha
+    txa
+    adc     _tablePtr+1
+    tax
+    pla
+    clc
+    adc     _x
+    bcc     L0019
+    inx
+L0019:
+    sta     ptr1
+    stx     ptr1+1
+    lda     #$53
+    ldy     #$00
+    sta     (ptr1),y
+
+after:
+
+;
+; y = 1;
+;
+    lda     #$01
+    sta     _y
+;
+; (*tablePtr)[y][x] = 83;
+;
+    ldx     #$00
+    lda     _y
+    jsr     aslax2
+    clc
+    adc     _tablePtr
+    sta     ptr1
+    txa
+    adc     _tablePtr+1
+    sta     ptr1+1
+    ldy     _x
+    lda     #$53
+    sta     (ptr1),y
+*/
+
+typedef unsigned char array_t[4][4];
+
+static array_t table = {
+    {12, 13, 14, 15},
+    { 8,  9, 10, 11},
+    { 4,  5,  6,  7},
+    { 0,  1,  2,  3}
+};
+static array_t *tablePtr = &table;
+
+static unsigned char y = 0, x;
+
+void pointed_array(void)
+{
+    x = 3;
+    y = 1;
+    (*tablePtr)[y][x] = 83;
+}
+
+int main(void)
+{
+    pointed_array();
+    return foo(2, 0) ? EXIT_SUCCESS : EXIT_FAILURE;
+}