Hi, PR102281 -ftrivial-auto-var-init=zero causes ice
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102281 Exposed multiple issues in the current padding clearing implementation of -ftrivial-auto-var-init: A. should check is_gimple_reg before adding the call to __builtin_clear_padding; (correctness) B. should check whether a type has padding before adding this call; (more efficient) C. For long double/Complex long double variables, if they are explicitly initialzied, should clear their padding during RTL phase when the variable is spilled into stack. in the fix to this bug, A is a must, B is better to add in. C is not needed, can be fixed in another bug, I have created a new PR 102781 to record this issue and will fix it later is needed. The patch for this Bug includes A + B. I have tested the patch on X86 and aarch64, bootstrapped and regression testing. Okay for trunk? Thanks. Qing. ============================= >From ca78d82d7fe9064c0dcae845d1e4df34601fc083 Mon Sep 17 00:00:00 2001 From: Qing Zhao <qing.z...@oracle.com> Date: Sat, 16 Oct 2021 17:15:23 +0000 Subject: [PATCH] PR 102281 (-ftrivial-auto-var-init=zero causes ice) Do not add call to __BUILTIN_CLEAR_PADDING when a variable is a gimple register or it might not have padding. gcc/ChangeLog: 2021-10-16 qing zhao <qing.z...@oracle.com> * gimplify.c (gimplify_decl_expr): Do not add call to __BUILTIN_CLEAR_PADDING when a variable is a gimple register or it might not have padding. (gimplify_init_constructor): Likewise. gcc/testsuite/ChangeLog: 2021-10-16 qing zhao <qing.z...@oracle.com> * c-c++-common/pr102281.c: New test. * gcc.target/i386/auto-init-2.c: Adjust testing case. * gcc.target/i386/auto-init-4.c: Likewise. * gcc.target/i386/auto-init-6.c: Likewise. * gcc.target/aarch64/auto-init-6.c: Likewise. --- gcc/gimplify.c | 19 ++++++++++++++++--- gcc/testsuite/c-c++-common/pr102281.c | 15 +++++++++++++++ .../gcc.target/aarch64/auto-init-6.c | 4 ++-- gcc/testsuite/gcc.target/i386/auto-init-2.c | 2 +- gcc/testsuite/gcc.target/i386/auto-init-4.c | 10 ++++------ gcc/testsuite/gcc.target/i386/auto-init-6.c | 7 ++++--- 6 files changed, 42 insertions(+), 15 deletions(-) create mode 100644 gcc/testsuite/c-c++-common/pr102281.c diff --git a/gcc/gimplify.c b/gcc/gimplify.c index d8e4b139349..82968017cd9 100644 --- a/gcc/gimplify.c +++ b/gcc/gimplify.c @@ -1954,8 +1954,14 @@ gimplify_decl_expr (tree *stmt_p, gimple_seq *seq_p) pattern initialization. In order to make the paddings as zeroes for pattern init, We should add a call to __builtin_clear_padding to clear the - paddings to zero in compatiple with CLANG. */ - if (flag_auto_var_init == AUTO_INIT_PATTERN) + paddings to zero in compatiple with CLANG. + We cannot insert this call if the variable is a gimple register + since __BUILTIN_CLEAR_PADDING assumes the variable is in memory. + As a result, if a long double/Complex long double variable will + spilled into stack later, its padding is 0XFE. */ + if (flag_auto_var_init == AUTO_INIT_PATTERN + && !is_gimple_reg (decl) + && clear_padding_type_may_have_padding_p (TREE_TYPE (decl))) gimple_add_padding_init_for_auto_var (decl, is_vla, seq_p); } } @@ -5388,8 +5394,15 @@ gimplify_init_constructor (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p, initialize paddings of object always to zero regardless of INIT_TYPE. Note, we will not insert this call if the aggregate variable has be completely cleared already or it's initialized - with an empty constructor. */ + with an empty constructor. We cannot insert this call if the + variable is a gimple register since __BUILTIN_CLEAR_PADDING assumes + the variable is in memory. As a result, if a long double/Complex long + double variable will be spilled into stack later, its padding cannot + be cleared with __BUILTIN_CLEAR_PADDING. we should clear its padding + when it is spilled into memory. */ if (is_init_expr + && !is_gimple_reg (object) + && clear_padding_type_may_have_padding_p (type) && ((AGGREGATE_TYPE_P (type) && !cleared && !is_empty_ctor) || !AGGREGATE_TYPE_P (type)) && is_var_need_auto_init (object)) diff --git a/gcc/testsuite/c-c++-common/pr102281.c b/gcc/testsuite/c-c++-common/pr102281.c new file mode 100644 index 00000000000..bfe9b08524b --- /dev/null +++ b/gcc/testsuite/c-c++-common/pr102281.c @@ -0,0 +1,15 @@ +/* PR102281 */ +/* { dg-do compile } */ +/* { dg-options "-ftrivial-auto-var-init=zero" } */ +long _mm_set_epi64x___q0; +__attribute__((__vector_size__(2 * sizeof(long)))) long long _mm_set_epi64x() { + return (__attribute__((__vector_size__(2 * sizeof(long)))) long long){ + _mm_set_epi64x___q0}; +} + +float _mm_set1_ps___F; +__attribute__((__vector_size__(4 * sizeof(float)))) float +__attribute___mm_set1_ps() { + return (__attribute__((__vector_size__(4 * sizeof(float)))) float){ + _mm_set1_ps___F}; +} diff --git a/gcc/testsuite/gcc.target/aarch64/auto-init-6.c b/gcc/testsuite/gcc.target/aarch64/auto-init-6.c index 27c16b33678..0456c66f496 100644 --- a/gcc/testsuite/gcc.target/aarch64/auto-init-6.c +++ b/gcc/testsuite/gcc.target/aarch64/auto-init-6.c @@ -1,6 +1,6 @@ /* Verify pattern initialization for complex type automatic variables. */ /* { dg-do compile } */ -/* { dg-options "-ftrivial-auto-var-init=pattern -fdump-rtl-expand" } */ +/* { dg-options "-ftrivial-auto-var-init=pattern" } */ _Complex long double result; @@ -15,4 +15,4 @@ _Complex long double foo() return result; } -/* { dg-final { scan-rtl-dump-times "0xfffffffffffffffe\\\]\\\) repeated x16" 3 "expand" } } */ +/* { dg-final { scan-assembler-times "word\t-16843010" 14 } } */ diff --git a/gcc/testsuite/gcc.target/i386/auto-init-2.c b/gcc/testsuite/gcc.target/i386/auto-init-2.c index e22930ae89b..0c59c62dacf 100644 --- a/gcc/testsuite/gcc.target/i386/auto-init-2.c +++ b/gcc/testsuite/gcc.target/i386/auto-init-2.c @@ -29,7 +29,7 @@ void foo() return; } -/* { dg-final { scan-rtl-dump-times "0xfffffffffffffffe" 2 "expand" } } */ +/* { dg-final { scan-rtl-dump-times "0xfffffffffffffffe" 1 "expand" } } */ /* { dg-final { scan-rtl-dump-times "0xfffffffffffffefe" 1 "expand" } } */ /* { dg-final { scan-rtl-dump-times "0xfffffffffefefefe" 2 "expand" { target lp64 } } } */ /* { dg-final { scan-rtl-dump-times "0xfefefefefefefefe" 3 "expand" { target lp64 } } } */ diff --git a/gcc/testsuite/gcc.target/i386/auto-init-4.c b/gcc/testsuite/gcc.target/i386/auto-init-4.c index 7b46c74a073..1803dd45842 100644 --- a/gcc/testsuite/gcc.target/i386/auto-init-4.c +++ b/gcc/testsuite/gcc.target/i386/auto-init-4.c @@ -1,6 +1,6 @@ /* Verify pattern initialization for floating point type automatic variables. */ /* { dg-do compile } */ -/* { dg-options "-ftrivial-auto-var-init=pattern -fdump-rtl-expand -march=x86-64 -mtune=generic -msse" } */ +/* { dg-options "-ftrivial-auto-var-init=pattern -march=x86-64 -mtune=generic -msse" } */ long double result; @@ -14,8 +14,6 @@ long double foo() return result; } -/* { dg-final { scan-rtl-dump-times "0xfffffffffefefefe" 1 "expand" { target { ! ia32 } } } } */ -/* { dg-final { scan-rtl-dump-times "\\\[0xfefefefefefefefe\\\]" 1 "expand" { target { ! ia32 } } } } */ -/* { dg-final { scan-rtl-dump-times "0xfffffffffffffffe\\\]\\\) repeated x16" 1 "expand" { target { ! ia32 } } } } */ -/* { dg-final { scan-rtl-dump-times "0xfffffffffefefefe" 2 "expand" { target ia32 } } } */ -/* { dg-final { scan-rtl-dump-times "\\\[0xfefefefefefefefe\\\]" 2 "expand" { target ia32 } } } */ + +/* { dg-final { scan-assembler-times "long\t-16843010" 5 { target { ! ia32 } } } } */ +/* { dg-final { scan-assembler-times "long\t-16843010" 3 { target { ia32 } } } } */ diff --git a/gcc/testsuite/gcc.target/i386/auto-init-6.c b/gcc/testsuite/gcc.target/i386/auto-init-6.c index f75081edce4..339f8bc2966 100644 --- a/gcc/testsuite/gcc.target/i386/auto-init-6.c +++ b/gcc/testsuite/gcc.target/i386/auto-init-6.c @@ -1,6 +1,6 @@ /* Verify pattern initialization for complex type automatic variables. */ /* { dg-do compile } */ -/* { dg-options "-ftrivial-auto-var-init=pattern -fdump-rtl-expand -march=x86-64 -mtune=generic -msse" } */ +/* { dg-options "-ftrivial-auto-var-init=pattern -march=x86-64 -mtune=generic -msse" } */ _Complex long double result; @@ -15,5 +15,6 @@ _Complex long double foo() return result; } -/* { dg-final { scan-rtl-dump-times "\\\[0xfefefefefefefefe\\\]" 1 "expand" } } */ -/* { dg-final { scan-rtl-dump-times "0xfffffffffffffffe\\\]\\\) repeated x16" 2 "expand" } } */ +/* { dg-final { scan-assembler-times "long\t-16843010" 10 { target { ! ia32 } } } } */ +/* { dg-final { scan-assembler-times "long\t-16843010" 6 { target { ia32 } } } } */ + -- 2.27.0
