| Summary: | [4.1 regression] ICE with -ftree-vectorize | ||
|---|---|---|---|
| Product: | gcc | Reporter: | James A. Morrison <phython> |
| Component: | target | Assignee: | Alan Modra <amodra> |
| Status: | RESOLVED FIXED | ||
| Severity: | normal | CC: | amodra, dje, gcc-bugs, pinskia |
| Priority: | P3 | Keywords: | ice-on-valid-code |
| Version: | 4.1.0 | ||
| Target Milestone: | 4.1.0 | ||
| URL: | http://gcc.gnu.org/ml/gcc-patches/2005-11/msg01916.html | ||
| Host: | powerpc-linux | Target: | powerpc-linux |
| Build: | powerpc-linux | Known to work: | 4.0.3 4.1.0 4.2.0 |
| Known to fail: | Last reconfirmed: | 2005-11-24 10:21:53 | |
| Bug Depends on: | 25212 | ||
| Bug Blocks: | |||
| Attachments: | preprocessed source | ||
Please attach preprocessed source. Hmm, r9, wtf. Any ways, we need the .i file :). Created attachment 10327 [details]
preprocessed source
Here is the preprocessed source. Sorry, I haven't had a change to run delta on it yet, nor can I reproduce this ICE without using -O3 -ftree-vectorize.
Reducing. I will finish reducing this after class (I stopped and started reducing a different testcase anyways). Actually this bug is too funny to reduce, reload is too funny for the life of me. Compiling with -da with a semi reduced testcases makes it pass. I'm not surprised that reducing this testcase isn't easy. Register pressure is needed to trigger the bug. The problem is that in
(insn:HI 2761 3601 2769 279 wmadec.c:1117 (set (reg:V4SF 280 [ vect_var_.655 ])
(mem:V4SF (and:SI (plus:SI (reg/f:SI 1824)
(reg:SI 284 [ base_off.641 ]))
(const_int -16 [0xfffffffffffffff0])) [4 S16 A128])) 628 {altivec_lvx_v4sf} (insn_list:REG_DEP_TRUE 2757 (nil))
(expr_list:REG_DEAD (reg:SI 284 [ base_off.641 ])
(nil)))
reg 1824 doesn't get a hard register, so is replaced with a stack slot
(insn:HI 2761 3601 2769 279 wmadec.c:1117 (set (reg:V4SF 89 12 [orig:280 vect_var_.655 ] [280])
(mem:V4SF (and:SI (plus:SI (plus:SI (reg/f:SI 1 1)
(reg:SI 11 11 [orig:284 base_off.641 ] [284]))
(const_int 16512 [0x4080]))
(const_int -16 [0xfffffffffffffff0])) [4 S16 A128])) 628 {altivec_lvx_v4sf} (insn_list:REG_DEP_TRUE 2757 (nil))
(expr_list:REG_DEAD (reg:SI 11 11 [orig:284 base_off.641 ] [284])
(nil)))
reload just tries to put the mem address, including the AND, into a reg. It needs to be taught that the AND should stay with the insn. The real address is the part inside the AND.
Oops, no, that's not a stack slot. That's a stack slot gone wrong. Where's the MEM for the slot? Indeed it's not a stack slot. Instead, reg 1824 is an invariant, equal to sfp+16512. Code in reload1.c:eliminate_regs_1 substitutes r1 for sfp, then reorganises the order of the additions, so we get (r1+r11)+const not (r1+const)+r11. This of course isn't a valid address on powerpc, where indexed addresses can't take an offset. In case it isn't obvious, I'm a little lost. Hopefully my analysis will let someone more familiar with reload sort this out. I think I've sorted this out after all.. Testing a fix. Subject: Bug 24997 Author: amodra Date: Mon Nov 28 03:52:01 2005 New Revision: 107591 URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=107591 Log: PR target/24997 * config/rs6000/rs6000.c (legitimate_indexed_address_p): Allow pattern generated by reload. * config/rs6000/predicates.md (indexed_or_indirect_operand): Use indexed_or_indirect_address. (indexed_or_indirect_address): Don't test for base reg. Call address_operand last. Make it a special predicate. Modified: trunk/gcc/ChangeLog trunk/gcc/config/rs6000/predicates.md trunk/gcc/config/rs6000/rs6000.c pr25212 has a more complete fix that I propose applying to the 4.1 branch. Fixed 4.1 by pr25212 commit. |
wmadec.c ICE's with: /home/jim/cvs/mplayer/ffmpeg/libavcodec/wmadec.c:1193: error: unrecognizable insn: (insn 4809 3267 2762 272 /home/jim/cvs/mplayer/ffmpeg/libavcodec/wmadec.c:1117 (set (reg:SI 9 9) (and:SI (plus:SI (reg:SI 27 27) (reg:SI 11 11 [orig:284 base_off.641 ] [284])) (const_int -16 [0xfffffffffffffff0]))) -1 (nil) (nil)) /home/jim/cvs/mplayer/ffmpeg/libavcodec/wmadec.c:1193: internal compiler error: in extract_insn, at recog.c:2084 the command line is: /usr/lib/gcc-snapshot/bin/gcc -O3 -g -Wall -Wno-switch -maltivec -mabi=altivec -DHAVE_AV_CONFIG_H -I.. -I/home/jim/cvs/mplayer/ffmpeg/libavutil -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_GNU_SOURCE -c -o wmadec.o /home/jim/cvs/mplayer/ffmpeg/libavcodec/wmadec.c The gcc-snapshot is from the debian package version 20051122-1, the ice also occurs in earlier versions of the package.