rs6000: Make cr5 allocatable

A comment in rs6000.h says "cr5 is not supposed to be used".  I checked
all ABIs, going as far back as PowerOpen (1994), and found no mention
of this.

Also document cr6 is used by some vector instructions.

From-SVN: r211811

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index a4a636d0230db2a4cde8ec224c79b57138b03bc5..76456542198757fa80aff8572265ccbffa1484a4 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2014-06-18  Segher Boessenkool  <segher@kernel.crashing.org>
+
+       * config/rs6000/rs6000.h (FIXED_REGISTERS): Update comment.
+       Remove cr5.
+       (REG_ALLOC_ORDER): Update comment.  Move cr5 earlier.
+
 2014-06-18  Kaz Kojima  <kkojima@gcc.gnu.org>
 
        PR target/61550

diff --git a/gcc/config/rs6000/rs6000.h b/gcc/config/rs6000/rs6000.h
index 3bd010476886999140f82da2d0560e3a5fe64fdf..569ae2d3f27ec24c2532f44588869e4d969b9928 100644 (file)
--- a/gcc/config/rs6000/rs6000.h
+++ b/gcc/config/rs6000/rs6000.h
@@ -978,8 +978,6 @@ enum data_align { align_abi, align_opt, align_both };
    On RS/6000, r1 is used for the stack.  On Darwin, r2 is available
    as a local register; for all other OS's r2 is the TOC pointer.
 
-   cr5 is not supposed to be used.
-
    On System V implementations, r13 is fixed and not available for use.  */
 
 #define FIXED_REGISTERS  \
@@ -987,7 +985,7 @@ enum data_align { align_abi, align_opt, align_both };
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \
-   0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1,         \
+   0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1,         \
    /* AltiVec registers.  */                      \
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \
@@ -1048,7 +1046,8 @@ enum data_align { align_abi, align_opt, align_both };
        fp13 - fp2      (not saved; incoming fp arg registers)
        fp1             (not saved; return value)
        fp31 - fp14     (saved; order given to save least number)
-       cr7, cr6        (not saved or special)
+       cr7, cr5        (not saved or special)
+       cr6             (not saved, but used for vector operations)
        cr1             (not saved, but used for FP operations)
        cr0             (not saved, but used for arithmetic operations)
        cr4, cr3, cr2   (saved)
@@ -1061,7 +1060,7 @@ enum data_align { align_abi, align_opt, align_both };
        r12             (not saved; if used for DImode or DFmode would use r13)
        ctr             (not saved; when we have the choice ctr is better)
        lr              (saved)
-       cr5, r1, r2, ap, ca (fixed)
+       r1, r2, ap, ca  (fixed)
        v0 - v1         (not saved or used for anything)
        v13 - v3        (not saved; incoming vector arg registers)
        v2              (not saved; incoming vector arg reg; return value)
@@ -1099,14 +1098,14 @@ enum data_align { align_abi, align_opt, align_both };
    33,                                                         \
    63, 62, 61, 60, 59, 58, 57, 56, 55, 54, 53, 52, 51,         \
    50, 49, 48, 47, 46,                                         \
-   75, 74, 69, 68, 72, 71, 70,                                 \
+   75, 73, 74, 69, 68, 72, 71, 70,                             \
    MAYBE_R2_AVAILABLE                                          \
    9, 10, 8, 7, 6, 5, 4,                                       \
    3, EARLY_R12 11, 0,                                         \
    31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19,         \
    18, 17, 16, 15, 14, 13, LATE_R12                            \
    66, 65,                                                     \
-   73, 1, MAYBE_R2_FIXED 67, 76,                               \
+   1, MAYBE_R2_FIXED 67, 76,                                   \
    /* AltiVec registers.  */                                   \
    77, 78,                                                     \
    90, 89, 88, 87, 86, 85, 84, 83, 82, 81, 80,                 \