2015-05-21 22:08 GMT+03:00 Vladimir Makarov <vmaka...@redhat.com>: > On 05/21/2015 05:54 AM, Ilya Enkovich wrote: >>> >>> Thanks. For me it looks like an inheritance bug. It is really hard >>> >to fix the bug w/o the source code. Could you send me your patch in >>> >order I can debug RA with it to investigate more. >>> > >> >> Sure! Here is a patch and a testcase. I applied patch to r222125. Cmd to >> reproduce: >> >> gcc -m32 -msse4.2 -O2 pr65105.c -S -march=slm -fPIE > > The problem is in sharing a subreg in different insns. Pseudo should be > shared but not their subregs. > > We have before inheritance: > > 28: r132:V2DI=r132:V2DI|r126:DI#0 > REG_DEAD r126:DI > REG_DEAD r118:DI > Inserting insn reload before: > 81: r132:V2DI=r118:DI#0 > Inserting insn reload after: > 82: r108:DI#0=r132:V2DI > ... > Creating newreg=135, assigning class SSE_REGS to r135 > 42: r135:V2DI=r135:V2DI&r108:DI#0 > REG_DEAD r127:DI > Inserting insn reload before: > 85: r135:V2DI=r127:DI#0 > Inserting insn reload after: > 86: r108:DI#0=r135:V2DI > > As subreg of 108 in original insns 28 and 42 are shared, The subregs of 108 > in insns 82 and 86 are shared too. During inheritance subpass we change > r108 in insn 82 onto r137. This change insn 86 too. > > Creating newreg=137 from oldreg=108, assigning class NO_REX_SSE_REGS > to inheritance r137 > Original reg change 108->137 (bb2): > 82: r137:DI#0=r132:V2DI > REG_DEAD r132:V2DI > Add original<-inheritance after: > 88: r108:DI=r137:DI > > Inheritance reuse change 108->137 (bb2): > 68: r124:V2DI=r137:DI#0 > > And now we are trying to do inheritance for insn #86: > > Creating newreg=138 from oldreg=108, assigning class NO_REX_SSE_REGS to > inheritance r138 > Original reg change 108->138 (bb3): > 86: r137:DI#0=r135:V2DI > REG_DEAD r135:V2DI > Add original<-inheritance after: > 89: r108:DI=r138:DI > > Inheritance reuse change 108->138 (bb3): > 64: r123:V2DI=r137:DI#0 > > and after that having a complete mess. We are trying to change r108 onto > r138, but r108 is already r137 because of sharing. Later we undo the second > inheritance creating even more mess. > > So, Ilya, to solve the problem you need to avoid sharing subregs for the > correct LRA/reload work. > >
Thanks a lot for your help! I'll fix it. Ilya
