On Wed, Jan 27, 2016 at 7:34 AM, Ilya Enkovich <enkovich....@gmail.com> wrote: > Hi, > > Currently STV pass may require a stack realignment if any > transformation occurs to enable SSE registers spill/fill. > It appears it's invalid to increase stack alignment requirements > at this point. Thus we have to either assume we need stack to be > aligned if are going to run STV pass or disable STV if stack is > not properly aligned. I suppose we shouldn't ignore explicitly > requested stack alignment not beeing sure we really optimize > anything (and STV is not an optimization frequiently applied). > So I think we may disable TARGET_STV for such cases as Jakub > suggested. This patch was bootstrapped and regtested on > x86_64-pc-linux-gnu. OK for trunk? >
> diff --git a/gcc/testsuite/gcc.target/i386/pr69454-1.c > b/gcc/testsuite/gcc.target/i386/pr69454-1.c > new file mode 100644 > index 0000000..12ecfd3 > --- /dev/null > +++ b/gcc/testsuite/gcc.target/i386/pr69454-1.c > @@ -0,0 +1,11 @@ > +/* { dg-do compile { target { ia32 } } } */ > +/* { dg-options "-O2 -msse2 -mno-accumulate-outgoing-args > -mpreferred-stack-boundary=2" } */ > + > +typedef struct { long long w64[2]; } V128; > +extern V128* fn2(void); > +long long a; > +V128 b; > +void fn1() { > + V128 *c = fn2(); > + c->w64[0] = a ^ b.w64[0]; > +} > diff --git a/gcc/testsuite/gcc.target/i386/pr69454-2.c > b/gcc/testsuite/gcc.target/i386/pr69454-2.c > new file mode 100644 > index 0000000..28bab93 > --- /dev/null > +++ b/gcc/testsuite/gcc.target/i386/pr69454-2.c > @@ -0,0 +1,13 @@ > +/* { dg-do compile { target { ia32 } } } */ > +/* { dg-options "-O2 -mpreferred-stack-boundary=2" } */ This needs: +/* { dg-options "-O2 -msse2 -mno-accumulate-outgoing-args -mpreferred-stack-boundary=2" } */ to trigger. > +extern void fn2 (); > +long long a, b; > + > +void fn1 () > +{ > + long long c = a; > + a = b ^ a; > + fn2 (); > + a = c; > +} Here is a different patch, which I believe is the right fix. -- H.J.
From 86e040399dd5ca6b23597be4aff5edb9ac2ab5d7 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" <hjl.to...@gmail.com> Date: Mon, 25 Jan 2016 12:31:45 -0800 Subject: [PATCH] Don't align DImode to 32 bits if the STV pass is enabled Since the STV pass uses SSE2 instructions on DImode which needs 64-bit alignment for DImode, don't align DImode to 32 bits if the STV pass is enabled. gcc/ PR target/69454 * config/i386/i386.c (convert_scalars_to_vector): Don't change stack alignment here. (ix86_minimum_alignment): Don't align DImode to 32 bits if the STV pass is enabled. gcc/testsuite/ PR target/69454 * gcc.target/i386/pr69454-1.c: New test. * gcc.target/i386/pr69454-2.c: Likewise. --- gcc/config/i386/i386.c | 16 ++++------------ gcc/testsuite/gcc.target/i386/pr69454-1.c | 11 +++++++++++ gcc/testsuite/gcc.target/i386/pr69454-2.c | 13 +++++++++++++ 3 files changed, 28 insertions(+), 12 deletions(-) create mode 100644 gcc/testsuite/gcc.target/i386/pr69454-1.c create mode 100644 gcc/testsuite/gcc.target/i386/pr69454-2.c diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c index cfbdf0f..8babdaf 100644 --- a/gcc/config/i386/i386.c +++ b/gcc/config/i386/i386.c @@ -3588,16 +3588,6 @@ convert_scalars_to_vector () bitmap_obstack_release (NULL); df_process_deferred_rescans (); - /* Conversion means we may have 128bit register spills/fills - which require aligned stack. */ - if (converted_insns) - { - if (crtl->stack_alignment_needed < 128) - crtl->stack_alignment_needed = 128; - if (crtl->stack_alignment_estimated < 128) - crtl->stack_alignment_estimated = 128; - } - return 0; } @@ -29299,8 +29289,10 @@ ix86_minimum_alignment (tree exp, machine_mode mode, return align; /* Don't do dynamic stack realignment for long long objects with - -mpreferred-stack-boundary=2. */ - if ((mode == DImode || (type && TYPE_MODE (type) == DImode)) + -mpreferred-stack-boundary=2. The STV pass uses SSE2 instructions + on DImode which needs 64-bit alignment for DImode. */ + if (!(TARGET_STV && TARGET_SSE2 && optimize > 1) + && (mode == DImode || (type && TYPE_MODE (type) == DImode)) && (!type || !TYPE_USER_ALIGN (type)) && (!decl || !DECL_USER_ALIGN (decl))) return 32; diff --git a/gcc/testsuite/gcc.target/i386/pr69454-1.c b/gcc/testsuite/gcc.target/i386/pr69454-1.c new file mode 100644 index 0000000..12ecfd3 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr69454-1.c @@ -0,0 +1,11 @@ +/* { dg-do compile { target { ia32 } } } */ +/* { dg-options "-O2 -msse2 -mno-accumulate-outgoing-args -mpreferred-stack-boundary=2" } */ + +typedef struct { long long w64[2]; } V128; +extern V128* fn2(void); +long long a; +V128 b; +void fn1() { + V128 *c = fn2(); + c->w64[0] = a ^ b.w64[0]; +} diff --git a/gcc/testsuite/gcc.target/i386/pr69454-2.c b/gcc/testsuite/gcc.target/i386/pr69454-2.c new file mode 100644 index 0000000..4820b76 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr69454-2.c @@ -0,0 +1,13 @@ +/* { dg-do compile { target { ia32 } } } */ +/* { dg-options "-O2 -msse2 -mno-accumulate-outgoing-args -mpreferred-stack-boundary=2" } */ + +extern void fn2 (void); +long long a, b; +void +fn1 (void) +{ + long long c = a; + a = b ^ a; + fn2 (); + a = c; +} -- 2.5.0