Re: [PATCH 2/2, x86, PR63534] Fix darwin bootstrap

[Evgeny Stupachenko <evstupac at gmail dot com>]

>What is ia32 specific on the test?
Just the fact the test fails on ia32 now, for 64 bit the test is very
simple, however we can test it as well.
Full patch with testcase:

2014-10-22  Evgeny Stupachenko  <evstupac@gmail.com>

        PR target/63534
        PR target/63618
        * cse.c (delete_trivially_dead_insns): Consider PIC register is used
        while it is pseudo.
        * dse.c (deletable_insn_p): Likewise.

        * gcc.target/i386/pr63618.c: New test.

diff --git a/gcc/cse.c b/gcc/cse.c
index be2f31b..92e6bf8 100644
--- a/gcc/cse.c
+++ b/gcc/cse.c
@@ -6953,6 +6953,12 @@ delete_trivially_dead_insns (rtx_insn *insns, int nreg)
       /* If no debug insns can be present, COUNTS is just an array
         which counts how many times each pseudo is used.  */
     }
+  /* Pseudo PIC register should be considered as used due to possible
+     new usages generated.  */
+  if (!reload_completed
+      && pic_offset_table_rtx
+      && REGNO (pic_offset_table_rtx) >= FIRST_PSEUDO_REGISTER)
+    counts[REGNO (pic_offset_table_rtx)]++;
   /* Go from the last insn to the first and delete insns that only set unused
      registers or copy a register to itself.  As we delete an insn, remove
      usage counts for registers it uses.
diff --git a/gcc/dce.c b/gcc/dce.c
index 5b7d36e..9a9d334 100644
--- a/gcc/dce.c
+++ b/gcc/dce.c
@@ -127,6 +127,11 @@ deletable_insn_p (rtx_insn *insn, bool fast,
bitmap arg_stores)
     if (HARD_REGISTER_NUM_P (DF_REF_REGNO (def))
        && global_regs[DF_REF_REGNO (def)])
       return false;
+    /* Initialization of pseudo PIC register should never be removed.  */
+    else if (!reload_completed
+            && DF_REF_REG (def) == pic_offset_table_rtx
+            && REGNO (pic_offset_table_rtx) >= FIRST_PSEUDO_REGISTER)
+      return false;

   body = PATTERN (insn);
   switch (GET_CODE (body))
diff --git a/gcc/testsuite/gcc.target/i386/pr63618.c
b/gcc/testsuite/gcc.target/i386/pr63618.c
new file mode 100644
index 0000000..2075071
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr63618.c
@@ -0,0 +1,34 @@
+/* PR target/63618 */
+/* { dg-do run } */
+/* { dg-options "-O2 -mtune=corei7 -fno-inline" } */
+/* { dg-additional-options "-msse4.2" { target sse4 } } */
+/* { dg-additional-options "-fpic" { target fpic } } */
+
+static const __float128 cf = 0.1E+10Q;
+
+__float128
+f128_square(__float128 x)
+{
+  return x * x;
+}
+
+__float128
+f128_p3(__float128 x)
+{
+  return x * x * x;
+}
+
+__float128
+cond_f128_square (__float128 x, int p)
+{
+  x = f128_p3 (x);
+  if (p)
+    x = f128_square(cf);
+  return x;
+}
+
+int main()
+{
+  __float128 x = cond_f128_square (cf, 1);
+  return (int)(x < cf);
+}

On Wed, Oct 22, 2014 at 8:01 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> On Wed, Oct 22, 2014 at 07:55:57PM +0400, Evgeny Stupachenko wrote:
>> There is a test for Linux x86 that also fails without the changes in the patch:
>>
>> ChangeLog:
>>
>> 2014-10-22  Evgeny Stupachenko  <evstupac@gmail.com>
>>
>>         PR rtl-optimization/63618
>>         * gcc.target/i386/pr63618.c: New.
>>
>> diff --git a/gcc/testsuite/gcc.target/i386/pr63618.c
>> b/gcc/testsuite/gcc.target/i386/pr63618.c
>> new file mode 100644
>> index 0000000..cf10a2b
>> --- /dev/null
>> +++ b/gcc/testsuite/gcc.target/i386/pr63618.c
>> @@ -0,0 +1,34 @@
>> +/* PR rtl-optimization/63618 */
>> +/* { dg-do run } */
>> +/* { dg-require-effective-target sse4 } */
>> +/* { dg-require-effective-target ia32 } */
>> +/* { dg-options "-O2 -msse4.2 -mtune=corei7 -fno-inline -fPIC" } */
>
> What is ia32 specific on the test?
> As for -msse4.2 and sse4 effective target, I'd say
> better would be to stick that to
> /* { dg-additional-options "-msse4.2" { target sse4 } } */
> Similarly, you want -fPIC only if { target fpic }, thus I'd say you want to
> start the test with:
> /* { dg-do run } */
> /* { dg-options "-O2 -mtune=corei7 -fno-inline" } */
> /* { dg-additional-options "-msse4.2" { target sse4 } } */
> /* { dg-additional-options "-fpic" { target fpic } } */
>
>         Jakub