| Message ID | alpine.DEB.2.02.1211071706360.17415@bulbul |
|---|---|
| State | New |
| Headers | show |
On Wed, Nov 07, 2012 at 05:26:58PM +0400, Kirill Batuzov wrote: > > diff --git a/tcg/tcg.c b/tcg/tcg.c > > index c3a7f19..1133438 100644 > > --- a/tcg/tcg.c > > +++ b/tcg/tcg.c > > @@ -1329,8 +1329,8 @@ static void tcg_liveness_analysis(TCGContext *s) > > the low part. The result can be optimized to a simple > > add or sub. This happens often for x86_64 guest when the > > cpu mode is set to 32 bit. */ > > - if (dead_temps[args[1]]) { > > - if (dead_temps[args[0]]) { > > + if (dead_temps[args[1]] && !mem_temps[1]) { > > + if (dead_temps[args[0]] && !mem_temps[0]) { > > This should be mem_temps[args[1]] and mem_temps[args[0]] I believe. > > > goto do_remove; > > } > > /* Create the single operation plus nop. */ > > @@ -1355,8 +1355,8 @@ static void tcg_liveness_analysis(TCGContext *s) > > nb_iargs = 2; > > nb_oargs = 2; > > /* Likewise, test for the high part of the operation dead. */ > > - if (dead_temps[args[1]]) { > > - if (dead_temps[args[0]]) { > > + if (dead_temps[args[1]] && !mem_temps[1]) { > > + if (dead_temps[args[0]] && !mem_temps[0]) { > > Same here. > > > goto do_remove; > > } > > gen_opc_buf[op_index] = op = INDEX_op_mul_i32; > > Looks like for x86_64 guest temp 0 is the env (always mem_temp), temp 1 - > cc_op. As a result it can accidentally remove high part of operation > when it is actually alive but will never optimize out whole operation > even if its output is really dead. > > I've attached a small patch to fix this issue. > > I was not able to boot gentoo install CD (amd64) with current trunk. > Boot process hangs soon after framebuffer initialization. With the patch > it boots successfully. Command line to reproduce: > > qemu-system-x86_64 -cdrom install-amd64-minimal-20121013.iso > > -- > Kirill Batuzov > From 33e1fc03934cebea8d32c98ea34961c80f05d94a Mon Sep 17 00:00:00 2001 > From: Kirill Batuzov <batuzovk@ispras.ru> > Date: Wed, 7 Nov 2012 15:26:38 +0400 > Subject: [PATCH] tcg: properly check that op's output needs to be synced to > memory > > Fix typo introduced in b3a1be87bac3a6aaa59bb88c1410f170dc9b22d5. > > Reported-by: Ruslan Savchenko <ruslan.savchenko@gmail.com> > Signed-off-by: Kirill Batuzov <batuzovk@ispras.ru> > --- > tcg/tcg.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/tcg/tcg.c b/tcg/tcg.c > index 42052db..35fba50 100644 > --- a/tcg/tcg.c > +++ b/tcg/tcg.c > @@ -1337,8 +1337,8 @@ static void tcg_liveness_analysis(TCGContext *s) > the low part. The result can be optimized to a simple > add or sub. This happens often for x86_64 guest when the > cpu mode is set to 32 bit. */ > - if (dead_temps[args[1]] && !mem_temps[1]) { > - if (dead_temps[args[0]] && !mem_temps[0]) { > + if (dead_temps[args[1]] && !mem_temps[args[1]]) { > + if (dead_temps[args[0]] && !mem_temps[args[0]]) { > goto do_remove; > } > /* Create the single operation plus nop. */ > @@ -1363,8 +1363,8 @@ static void tcg_liveness_analysis(TCGContext *s) > nb_iargs = 2; > nb_oargs = 2; > /* Likewise, test for the high part of the operation dead. */ > - if (dead_temps[args[1]] && !mem_temps[1]) { > - if (dead_temps[args[0]] && !mem_temps[0]) { > + if (dead_temps[args[1]] && !mem_temps[args[1]]) { > + if (dead_temps[args[0]] && !mem_temps[args[0]]) { > goto do_remove; > } > gen_opc_buf[op_index] = op = INDEX_op_mul_i32; Thanks, applied.
From 33e1fc03934cebea8d32c98ea34961c80f05d94a Mon Sep 17 00:00:00 2001 From: Kirill Batuzov <batuzovk@ispras.ru> Date: Wed, 7 Nov 2012 15:26:38 +0400 Subject: [PATCH] tcg: properly check that op's output needs to be synced to memory Fix typo introduced in b3a1be87bac3a6aaa59bb88c1410f170dc9b22d5. Reported-by: Ruslan Savchenko <ruslan.savchenko@gmail.com> Signed-off-by: Kirill Batuzov <batuzovk@ispras.ru> --- tcg/tcg.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/tcg/tcg.c b/tcg/tcg.c index 42052db..35fba50 100644 --- a/tcg/tcg.c +++ b/tcg/tcg.c @@ -1337,8 +1337,8 @@ static void tcg_liveness_analysis(TCGContext *s) the low part. The result can be optimized to a simple add or sub. This happens often for x86_64 guest when the cpu mode is set to 32 bit. */ - if (dead_temps[args[1]] && !mem_temps[1]) { - if (dead_temps[args[0]] && !mem_temps[0]) { + if (dead_temps[args[1]] && !mem_temps[args[1]]) { + if (dead_temps[args[0]] && !mem_temps[args[0]]) { goto do_remove; } /* Create the single operation plus nop. */ @@ -1363,8 +1363,8 @@ static void tcg_liveness_analysis(TCGContext *s) nb_iargs = 2; nb_oargs = 2; /* Likewise, test for the high part of the operation dead. */ - if (dead_temps[args[1]] && !mem_temps[1]) { - if (dead_temps[args[0]] && !mem_temps[0]) { + if (dead_temps[args[1]] && !mem_temps[args[1]]) { + if (dead_temps[args[0]] && !mem_temps[args[0]]) { goto do_remove; } gen_opc_buf[op_index] = op = INDEX_op_mul_i32; -- 1.7.9.5