Re-merge patch and fixes (was: x86_64 gcc build failure with 2011.01-0)

[Andrew Stubbs]

From the Ubuntu build log:
   http://launchpadlibrarian.net/62080751/buildlog_ubuntu-natty-amd64.gcc-4.5_4.5.2-1ubuntu4_FAILEDTOBUILD.txt.gz

../../src/gcc/coverage.c: In function 'htab_counts_entry_hash':
../../src/gcc/coverage.c:148:1: error: unrecognizable insn:
(insn 25 7 26 2 ../../src/gcc/coverage.c:147 (set (reg:DI 1 dx)
        (mem/s:SI (plus:DI (reg/v/f:DI 5 di [orig:64 of ] [64])
                (const_int 4 [0x4])) [4 entry_2->ctr+0 S4 A32])) -1 (nil))
../../src/gcc/coverage.c:148:1: internal compiler error: in extract_insn, at recog.c:2104
Please submit a full bug report,
with preprocessed source if appropriate.
See <file:///usr/share/doc/gcc-4.5/README.Bugs> for instructions.

On closer inspection, our own build log shows the problem, but in a different place, and it did not affect the test run, apparently:
  http://ex.seabright.co.nz/build/gcc-linaro-4.5-2011.01-0/logs/x86_64-lucid-cbuild24-orion/gcc-build.txt

We should probably check the build status in addition to the test results!

[Ulrich Weigand (uweigand)]

The invalid RTL was introduced by the following peephole in i386.md:

;; After splitting up read-modify operations, array accesses with memory
;; operands might end up in form:
;; sall $2, %eax
;; movl 4(%esp), %edx
;; addl %edx, %eax
;; instead of pre-splitting:
;; sall $2, %eax
;; addl 4(%esp), %eax
;; Turn it into:
;; movl 4(%esp), %edx
;; leal (%edx,%eax,4), %eax

(define_peephole2
  [(match_scratch:SI 5 "r")
   (parallel [(set (match_operand 0 "register_operand" "")
                   (ashift (match_operand 1 "register_operand" "")
                           (match_operand 2 "const_int_operand" "")))
               (clobber (reg:CC FLAGS_REG))])
   (parallel [(set (match_operand 3 "register_operand" "")
                   (plus (match_dup 0)
                         (match_operand 4 "x86_64_general_operand" "")))
                   (clobber (reg:CC FLAGS_REG))])]
  "INTVAL (operands[2]) >= 0 && INTVAL (operands[2]) <= 3
   /* Validate MODE for lea. */
   && ((!TARGET_PARTIAL_REG_STALL
        && (GET_MODE (operands[0]) == QImode
            || GET_MODE (operands[0]) == HImode))
       || GET_MODE (operands[0]) == SImode
       || (TARGET_64BIT && GET_MODE (operands[0]) == DImode))
   /* We reorder load and the shift. */
   && !reg_overlap_mentioned_p (operands[0], operands[4])"
  [(set (match_dup 5) (match_dup 4))
   (set (match_dup 0) (match_dup 1))]
{
  enum machine_mode mode = GET_MODE (operands[1]) == DImode ? DImode : SImode;
  int scale = 1 << INTVAL (operands[2]);
  rtx index = gen_lowpart (Pmode, operands[1]);
  rtx base = gen_lowpart (Pmode, operands[5]);
  rtx dest = gen_lowpart (mode, operands[3]);

  operands[1] = gen_rtx_PLUS (Pmode, base,
                              gen_rtx_MULT (Pmode, index, GEN_INT (scale)));
  if (mode != Pmode)
    operands[1] = gen_rtx_SUBREG (mode, operands[1], 0);
  operands[5] = base;
  operands[0] = dest;
})

Note how operands[5] is always DImode, while operands[4] may be some other mode.

[Ulrich Weigand (uweigand)]

This was fixed in mainline as PR target/44721:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44721

[Ulrich Weigand (uweigand)]

Note that there were two additional bugs in mainline also introduced by the same peephole patch:

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44722
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44727

[Launchpad Janitor (janitor)]

This bug was fixed in the package gcc-4.5 - 4.5.2-1ubuntu5

---------------
gcc-4.5 (4.5.2-1ubuntu5) natty; urgency=low

  * Update the Linaro support to the 4.5 2011.01-1 release. LP: #701733.
 -- Matthias Klose <email address hidden> Thu, 13 Jan 2011 23:52:30 +0100

[Michael Hope (michaelh1)]

This patch was reverted in the 2011.01-1 release. Renaming this ticket so that the patch and follow up fixes can be tracked.

[Michael Hope (michaelh1)]

Andrew, what's the status of this one? The upstream fix and follow on fixes seem to have been done.

[Andrew Stubbs (ams-codesourcery)]

These patches were re-merged in lp:gcc-linaro/4.5,revno=99475, and released in 4.5-2011.03-0.