PATCH: PR target/52146: [x32] - Wrong code to access addresses 0x80000000 to 0xFFFFFFFF

[H.J. Lu]

Hi,

Since constant address in x32 is signed extended to 64bit, negative
displacement without base nor index is out of range.  OK for trunk?

Thanks.


H.J.
---
gcc/

2012-02-10  H.J. Lu  <hongjiu...@intel.com>

        PR target/52146
        * config/i386/i386.c (ix86_legitimate_address_p): Disallow
        negative constant address for x32.

gcc/testsuite/

2012-02-10  H.J. Lu  <hongjiu...@intel.com>

        PR target/52146
        * gcc.target/i386/pr52146.c: New.

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 009dd53..0bb94a7 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -12107,6 +12107,15 @@ ix86_legitimate_address_p (enum machine_mode mode 
ATTRIBUTE_UNUSED,
                   || !ix86_legitimate_constant_p (Pmode, disp)))
        /* Displacement is not constant.  */
        return false;
+      else if (TARGET_X32
+              && !base
+              && !index
+              && CONST_INT_P (disp)
+              && INTVAL (disp) < 0)
+       /* Since constant address in x32 is signed extended to 64bit,
+          negative displacement without base nor index is out of
+          range.  */
+       return false;
       else if (TARGET_64BIT
               && !x86_64_immediate_operand (disp, VOIDmode))
        /* Displacement is out of range.  */
diff --git a/gcc/testsuite/gcc.target/i386/pr52146.c 
b/gcc/testsuite/gcc.target/i386/pr52146.c
new file mode 100644
index 0000000..68bdeff
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr52146.c
@@ -0,0 +1,17 @@
+/* { dg-do compile { target { { i?86-*-linux* x86_64-*-linux* } && { ! { ia32 
} } } } } */
+/* { dg-options "-O2 -mx32" } */
+
+void test1() {
+  int* apic_tpr_addr = (int *)0xfee00080;
+  *apic_tpr_addr += 4;
+}
+void test2() {
+  volatile int* apic_tpr_addr = (int *)0xfee00080;
+  *apic_tpr_addr = 0;
+}
+void test3() {
+  volatile int* apic_tpr_addr = (int *)0x7fffffff;
+  *apic_tpr_addr = 0;
+}
+
+/* { dg-final { scan-assembler-not "-18874240" } } */