[PATCH] Fix i686 miscompilation

[Jakub Jelinek <jakub at redhat dot com>]

Hi!

The testcase below is miscompiled at -O2 -mcpu=i686 (and -O1 -mcpu=i686 as
well). The issue is that the (c & 0x80) test becomes
testl $-128, %edi
while it should be
testl $128, %edi
The thing is that if we widen the insn from QImode to SImode, we have to
make sure the topmost 24 bits are cleared.
I found a cut'n'paste thing in addqi_1_lea as well during skimming for
similar potential bugs.

Fixed by following patch, bootstrapped on i386-redhat-linux, no regressions.
Ok to commit?

2001-01-29  Jakub Jelinek  <jakub@redhat.com>

	* config/i386/i386.md (addqi_1_lea): Fix mode (QI instead of HI).
	(testqi_1, andqi_2): If widening to SImode, make sure CONST_INT does
	not have any upper bits set.

	* gcc.c-torture/execute/20010129-1.c: New test.
	* gcc.c-torture/execute/20010129-1.x: Add -mcpu=i686 on ia32.

--- gcc/config/i386/i386.md.jj	Wed Jan 17 14:24:28 2001
+++ gcc/config/i386/i386.md	Mon Jan 29 15:25:28 2001
@@ -4983,10 +4983,10 @@
   [(set (attr "type")
      (if_then_else (eq_attr "alternative" "3")
 	(const_string "lea")
-	(if_then_else (match_operand:HI 2 "incdec_operand" "")
+	(if_then_else (match_operand:QI 2 "incdec_operand" "")
 	   (const_string "incdec")
 	   (const_string "alu"))))
-   (set_attr "mode" "HI,HI,SI,SI")])
+   (set_attr "mode" "QI,QI,SI,SI")])
 
 (define_insn "*addqi_1"
   [(set (match_operand:QI 0 "nonimmediate_operand" "=qm,q,r")
@@ -5959,11 +5959,17 @@
 			 (match_operand:QI 1 "nonmemory_operand" "n,n,qn,n"))
 		 (const_int 0)))]
   "ix86_match_ccmode (insn, CCNOmode)"
-  "@
-   test{b}\\t{%1, %0|%0, %1} 
-   test{b}\\t{%1, %0|%0, %1} 
-   test{b}\\t{%1, %0|%0, %1} 
-   test{l}\\t{%1, %k0|%k0, %1}"
+  "*
+{
+  if (which_alternative == 3)
+    {
+      if (GET_CODE (operands[1]) == CONST_INT
+	  && (INTVAL (operands[1]) & 0xffffff00))
+	operands[1] = GEN_INT (INTVAL (operands[1]) & 0xff);
+      return \"test{l}\\t{%1, %k0|%k0, %1}\";
+    }
+  return \"test{b}\\t{%1, %0|%0, %1}\";
+}"
   [(set_attr "type" "test")
    (set_attr "modrm" "0,1,1,1")
    (set_attr "mode" "QI,QI,QI,SI")
@@ -6283,10 +6289,17 @@
 	(and:QI (match_dup 1) (match_dup 2)))]
   "ix86_match_ccmode (insn, CCNOmode)
    && ix86_binary_operator_ok (AND, QImode, operands)"
-  "@
-   and{b}\\t{%2, %0|%0, %2}
-   and{b}\\t{%2, %0|%0, %2}
-   and{l}\\t{%2, %k0|%k0, %2}"
+  "*
+{
+  if (which_alternative == 2)
+    {
+      if (GET_CODE (operands[2]) == CONST_INT
+          && (INTVAL (operands[2]) & 0xffffff00))
+        operands[2] = GEN_INT (INTVAL (operands[2]) & 0xff);
+      return \"and{l}\\t{%2, %k0|%k0, %2}\";
+    }
+  return \"and{b}\\t{%2, %0|%0, %2}\";
+}"
   [(set_attr "type" "alu")
    (set_attr "mode" "QI,QI,SI")])
 
--- gcc/testsuite/gcc.c-torture/execute/20010129-1.x.jj	Mon Jan 29 14:30:39 2001
+++ gcc/testsuite/gcc.c-torture/execute/20010129-1.x	Mon Jan 29 14:31:26 2001
@@ -0,0 +1,4 @@
+if { [istarget "i?86-*-*"] } {
+  set additional_flags "-mcpu=i686"
+}
+return 0
--- gcc/testsuite/gcc.c-torture/execute/20010129-1.c.jj	Mon Jan 29 14:30:56 2001
+++ gcc/testsuite/gcc.c-torture/execute/20010129-1.c	Mon Jan 29 14:23:43 2001
@@ -0,0 +1,64 @@
+long baz1 (void *a)
+{
+  static long l;
+  return l++;
+}
+
+int baz2 (const char *a)
+{
+  return 0;
+}
+
+int baz3 (int i)
+{
+  if (!i)
+    abort ();
+  return 1;
+}
+
+void **bar;
+
+int foo (void *a, long b, int c)
+{
+  int d = 0, e, f = 0, i;
+  char g[256];
+  void **h;
+
+  g[0] = '\n';
+  g[1] = 0;
+
+  while (baz1 (a) < b) {
+    if (g[0] != ' ' && g[0] != '\t') {
+      f = 1;
+      e = 0;
+      if (!d && baz2 (g) == 0) {
+	if ((c & 0x10) == 0)
+	  continue;
+	e = d = 1;
+      }
+      if (!((c & 0x10) && (c & 0x4000) && e) && (c & 2))
+	continue;
+      if ((c & 0x2000) && baz2 (g) == 0)
+	continue;
+      if ((c & 0x1408) && baz2 (g) == 0)
+	continue;
+      if ((c & 0x200) && baz2 (g) == 0)
+	continue;
+      if (c & 0x80) {
+	for (h = bar, i = 0; h; h = (void **)*h, i++)
+	  if (baz3 (i))
+	    break;
+      }
+      f = 0;
+    }
+  }
+  return 0;
+}
+
+int main ()
+{
+  void *n = 0;
+  bar = &n;
+  foo (&n, 1, 0xc811);
+  exit (0);
+}

	Jakub