[patch,avr,applied] Fix PR116390

[Georg-Johann Lay]

This fixes an ICE due to some typos in avr_out_movsi_mr_r_reg_disp_tiny
that didn't use operands[1] when it was required.

Johann

--

AVR: target/116390 - Fix an avrtiny asm out template.

        PR target/116390
gcc/
        * config/avr/avr.cc (avr_out_movsi_mr_r_reg_disp_tiny): Fix
        output templates for the reg_base == reg_src and
        reg_src == reg_base - 2 cases.
gcc/testsuite/
        * gcc.target/avr/torture/pr116390.c: New test.
diff --git a/gcc/config/avr/avr.cc b/gcc/config/avr/avr.cc
index 8d59a6babed..8c19bcb34a6 100644
--- a/gcc/config/avr/avr.cc
+++ b/gcc/config/avr/avr.cc
@@ -5638,33 +5638,33 @@ avr_out_movsi_mr_r_reg_disp_tiny (rtx op[], int *l)
   rtx src = op[1];
   rtx base = XEXP (dest, 0);
   int reg_base = REGNO (XEXP (base, 0));
-  int reg_src =true_regnum (src);
+  int reg_src = true_regnum (src);
 
   if (reg_base == reg_src)
     {
       *l = 11;
-      return ("mov __tmp_reg__,%A2"        CR_TAB
-	      "mov __zero_reg__,%B2"       CR_TAB
+      return ("mov __tmp_reg__,%A1"        CR_TAB
+	      "mov __zero_reg__,%B1"       CR_TAB
 	      TINY_ADIW (%I0, %J0, %o0)    CR_TAB
 	      "st %b0+,__tmp_reg__"        CR_TAB
 	      "st %b0+,__zero_reg__"       CR_TAB
-	      "st %b0+,%C2"                CR_TAB
-	      "st %b0,%D2"                 CR_TAB
+	      "st %b0+,%C1"                CR_TAB
+	      "st %b0,%D1"                 CR_TAB
 	      "clr __zero_reg__"           CR_TAB
 	      TINY_SBIW (%I0, %J0, %o0+3));
     }
   else if (reg_src == reg_base - 2)
     {
-      *l = 11;
-      return ("mov __tmp_reg__,%C2"         CR_TAB
-	      "mov __zero_reg__,%D2"        CR_TAB
-	      TINY_ADIW (%I0, %J0, %o0)     CR_TAB
-	      "st %b0+,%A0"                 CR_TAB
-	      "st %b0+,%B0"                 CR_TAB
-	      "st %b0+,__tmp_reg__"         CR_TAB
-	      "st %b0,__zero_reg__"         CR_TAB
-	      "clr __zero_reg__"            CR_TAB
-	      TINY_SBIW (%I0, %J0, %o0+3));
+      // This awkward case can occur when ext-dce turns zero-extend:SI(HI)
+      // into a paradoxical subreg, which register allocation may turn into
+      // something like *(R28:HI + 7) = R26:SI.  There is actually no need
+      // to store the upper 2 bytes of R26:SI as they are unused rubbish.
+      // See PR116390.
+      *l = 6;
+      return (TINY_ADIW (%I0, %J0, %o0)     CR_TAB
+	      "st %b0+,%A1"                 CR_TAB
+	      "st %b0,%B1"                  CR_TAB
+	      TINY_SBIW (%I0, %J0, %o0+1));
     }
   *l = 8;
   return (TINY_ADIW (%I0, %J0, %o0)     CR_TAB
diff --git a/gcc/testsuite/gcc.target/avr/torture/pr116390.c b/gcc/testsuite/gcc.target/avr/torture/pr116390.c
new file mode 100644
index 00000000000..70c1ad62936
--- /dev/null
+++ b/gcc/testsuite/gcc.target/avr/torture/pr116390.c
@@ -0,0 +1,71 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-std=c99" } */
+
+typedef struct
+{
+    int i;
+} MyStruct;
+
+void f_ic (int, char);
+void f_pi (char const *, int);
+void f_iic (int, int, char);
+
+const MyStruct *f_rms (void);
+
+char *f_rcp (void);
+int f_ri (void);
+
+void badFoo (void)
+{
+    const MyStruct* ps = f_rms ();
+    const char* pc = f_rcp ();
+
+    unsigned n1 = f_rcp () - pc;
+
+    if (n1)
+    {
+        long n2 = n1 - ps->i;
+        if (n2 > 0)
+        {
+            if (f_ri ())
+                n2 = n1;
+
+            if (f_ri ())
+            {
+                f_iic (1, 2 * n2, ' ');
+            }
+            else
+                f_pi (pc, n2);
+        }
+        if (ps->i > 0)
+        {
+            if (n2 >= 0)
+                f_pi (pc + n2, ps->i);
+            else
+            {
+                f_ic (n2, ' ');
+            }
+        }
+
+        const int which = f_ri ();
+        switch (which)
+        {
+        case 1:
+            if (f_ri ())
+                f_rcp ()[1] = ' ';
+            break;
+
+        case 2:
+            f_pi (f_rcp (), 1);
+            break;
+
+        case 3:
+            if (f_ri () && n1 < 0)
+                f_ic (n1, ' ');
+            else
+                f_rcp ()[1] = ' ';
+            break;
+
+        }
+    }
+}