From: Eric Botcazou <ebotcazou@libertysurf.fr>
Date: Wed, 19 Mar 2003 19:54:27 +0000 (+0100)
Subject: re PR rtl-optimization/8746 (gcc miscompiles Linux kernel ppa driver on x86)
X-Git-Tag: releases/gcc-3.2.3~92
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f4e4a9eec38ec6aac23280eae8044d38bb3eafe3;p=thirdparty%2Fgcc.git

re PR rtl-optimization/8746 (gcc miscompiles Linux kernel ppa driver on x86)

	PR optimization/8746
	Backport from mainline:

	Thu Jun  6 23:14:46 CEST 2002  Jan Hubicka<jh@suse.cz>

	* i386.md (and promoting splitters): Disable QI to SImode promoting
	when doing so changes immediate to be 32bit.

From-SVN: r64593
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 3449fec285a9..d51e167d32e8 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,13 @@
+2003-03-19  Eric Botcazou  <ebotcazou@libertysurf.fr>
+
+	PR optimization/8746
+	Backport from mainline:
+
+	Thu Jun  6 23:14:46 CEST 2002  Jan Hubicka<jh@suse.cz>
+
+	* i386.md (and promoting splitters): Disable QI to SImode promoting
+	when doing so changes immediate to be 32bit.
+
 2003-03-19  Jakub Jelinek  <jakub@redhat.com>
 
 	* stmt.c (expand_start_case): Call emit_queue ().
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index d615a5017a86..34cd0da1aeea 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -16875,6 +16875,8 @@
    && ix86_match_ccmode (insn, CCNOmode)
    && (GET_MODE (operands[0]) == HImode
        || (GET_MODE (operands[0]) == QImode 
+	   /* Ensure that the operand will remain sign extended immediate.  */
+	   && INTVAL (operands[2]) >= 0
 	   && (TARGET_PROMOTE_QImode || optimize_size)))"
   [(parallel [(set (reg:CCNO 17)
 		   (compare:CCNO (and:SI (match_dup 1) (match_dup 2))
@@ -16888,16 +16890,17 @@
    operands[0] = gen_lowpart (SImode, operands[0]);
    operands[1] = gen_lowpart (SImode, operands[1]);")
 
+; Don't promote the QImode tests, as i386 don't have encoding of
+; the test instruction with 32bit sign extended immediate and thus
+; the code grows.
 (define_split
   [(set (reg 17)
-	(compare (and (match_operand 0 "aligned_operand" "")
-		      (match_operand 1 "const_int_operand" ""))
+	(compare (and (match_operand:HI 0 "aligned_operand" "")
+		      (match_operand:HI 1 "const_int_operand" ""))
 		 (const_int 0)))]
   "! TARGET_PARTIAL_REG_STALL && reload_completed
    && ix86_match_ccmode (insn, CCNOmode)
-   && (GET_MODE (operands[0]) == HImode
-       || (GET_MODE (operands[0]) == QImode 
-	   && (TARGET_PROMOTE_QImode || optimize_size)))"
+   && GET_MODE (operands[0]) == HImode"
   [(set (reg:CCNO 17)
 	(compare:CCNO (and:SI (match_dup 0) (match_dup 1))
 		      (const_int 0)))]
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index e2a81bf5e4ff..6286e197afe8 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2003-03-19  Eric Botcazou  <ebotcazou@libertysurf.fr>
+
+	* gcc.dg/i386-signbit-1.c: New test.
+
 2003-03-19  Jakub Jelinek  <jakub@redhat.com>
 
 	* gcc.c-torture/execute/20030313-1.c: New test.
diff --git a/gcc/testsuite/gcc.dg/i386-signbit-1.c b/gcc/testsuite/gcc.dg/i386-signbit-1.c
new file mode 100644
index 000000000000..ef162297dc48
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/i386-signbit-1.c
@@ -0,0 +1,28 @@
+/* PR optimization/8746 */
+/* { dg-do run } */
+/* { dg-options "-mcpu=i586 -O" { target i?86-*-* } } */
+
+extern void abort (void);
+
+unsigned char r0;
+
+int foo(int x)
+{
+  unsigned char r = x&0xf0;
+
+  if (!(r&0x80))
+  {
+    r0 = r;
+    return 0;
+  }
+  else
+    return 1;
+}
+
+int main(void)
+{
+  if (foo(0x80) != 1)
+    abort();
+
+   return 0;
+}