We can't place a TLS call before a conditional jump in a basic block like
(code_label 13 11 14 4 2 (nil) [1 uses])
(note 14 13 16 4 [bb 4] NOTE_INSN_BASIC_BLOCK)
(jump_insn 16 14 17 4 (set (pc)
(if_then_else (le (reg:CCNO 17 flags)
(const_int 0 [0]))
(label_ref 27)
(pc))) "x.c":10:21 discrim 1 1462 {*jcc}
(expr_list:REG_DEAD (reg:CCNO 17 flags)
(int_list:REG_BR_PROB 628353713 (nil)))
-> 27)
since the TLS call will clobber flags register. Instead, we should place
such call before all register setting basic blocks which dominate the
current basic block.
NB: GNU2 TLS:
(insn 66 2 5 2 (parallel [
(set (reg:DI 116)
(plus:DI (unspec:DI [
(symbol_ref:DI ("_TLS_MODULE_BASE_") [flags 0x10])
(unspec:DI [
(symbol_ref:DI ("_TLS_MODULE_BASE_") [flags 0x10])
] UNSPEC_TLSDESC)
(reg/f:DI 7 sp)] UNSPEC_TLSDESC)
(const:DI (unspec:DI [
(symbol_ref:DI ("tv_cache") [flags 0x5a])
] UNSPEC_DTPOFF))))
(clobber (reg:CC 17 flags))]) 1678 {*tls_dynamic_gnu2_combine_64_di}
(nil))
only clobbers flags register.
gcc/
PR target/121572
* config/i386/i386-features.cc (ix86_place_single_tls_call): Also
search for REG_DEAD notes if flag register is alive. Place the
TLS call before all FLAGS_REG setting BBs for conditional jump.
gcc/testsuite/
PR target/121572
* gcc.target/i386/pr121572-1a.c: New test.
* gcc.target/i386/pr121572-1b.c: Likewise.
Signed-off-by: H.J. Lu <hjl.to...@gmail.com>
---
gcc/config/i386/i386-features.cc | 41 ++++++++++++++++++++-
gcc/testsuite/gcc.target/i386/pr121572-1a.c | 40 ++++++++++++++++++++
gcc/testsuite/gcc.target/i386/pr121572-1b.c | 18 +++++++++
3 files changed, 98 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/gcc.target/i386/pr121572-1a.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr121572-1b.c
diff --git a/gcc/config/i386/i386-features.cc b/gcc/config/i386/i386-features.cc
index f0bdc5c1880..7cdf98c5778 100644
--- a/gcc/config/i386/i386-features.cc
+++ b/gcc/config/i386/i386-features.cc
@@ -3748,6 +3748,7 @@ ix86_place_single_tls_call (rtx dest, rtx val,
x86_cse_kind kind,
bb = get_immediate_dominator (CDI_DOMINATORS,
bb->loop_father->header);
+place_tls_call:
rtx_insn *insn = BB_HEAD (bb);
while (insn && !NONDEBUG_INSN_P (insn))
{
@@ -3837,7 +3838,7 @@ ix86_place_single_tls_call (rtx dest, rtx val,
x86_cse_kind kind,
&& bitmap_bit_p (in, i))
bitmap_set_bit (live_caller_saved_regs, i);
- if (!bitmap_empty_p (live_caller_saved_regs))
+ if (flags_live_p || !bitmap_empty_p (live_caller_saved_regs))
{
/* Search for REG_DEAD notes in this basic block. */
FOR_BB_INSNS (bb, insn)
@@ -3845,6 +3846,44 @@ ix86_place_single_tls_call (rtx dest, rtx val,
x86_cse_kind kind,
if (!NONDEBUG_INSN_P (insn))
continue;
+ if (JUMP_P (insn))
+ {
+ /* This must be a conditional jump. */
+ rtx label = JUMP_LABEL (insn);
+ if (label == nullptr
+ || ANY_RETURN_P (label)
+ || !(LABEL_P (label) || SYMBOL_REF_P (label)))
+ gcc_unreachable ();
+
+ rtx_insn *set_insn;
+ basic_block set_bb;
+ auto_bitmap set_bbs;
+
+ /* Get all BBs which define FLAGS_REG and dominate the
+ current BB from all DEFs of FLAGS_REG. */
+ for (df_ref def = DF_REG_DEF_CHAIN (FLAGS_REG);
+ def;
+ def = DF_REF_NEXT_REG (def))
+ if (!DF_REF_IS_ARTIFICIAL (def)
+ && !DF_REF_FLAGS_IS_SET (def, DF_REF_MAY_CLOBBER)
+ && !DF_REF_FLAGS_IS_SET (def, DF_REF_MUST_CLOBBER))
+ {
+ set_insn = DF_REF_INSN (def);
+ set = single_set (set_insn);
+ gcc_assert (set);
+ set_bb = DF_REF_BB (def);
+ if (dominated_by_p (CDI_DOMINATORS, bb, set_bb))
+ bitmap_set_bit (set_bbs, set_bb->index);
+ }
+
+ /* Place the call before all FLAGS_REG setting BBs since
+ we can't place a call before nor after a conditional
+ jump. */
+ bb = nearest_common_dominator_for_set (CDI_DOMINATORS,
+ set_bbs);
+ goto place_tls_call;
+ }
+
/* Check if FLAGS register is live. */
set = single_set (insn);
if (set)
diff --git a/gcc/testsuite/gcc.target/i386/pr121572-1a.c
b/gcc/testsuite/gcc.target/i386/pr121572-1a.c
new file mode 100644
index 00000000000..179a1a9e66c
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr121572-1a.c
@@ -0,0 +1,40 @@
+/* { dg-do compile { target *-*-linux* } } */
+/* { dg-options "-O0 -fpic -fplt -mtls-dialect=gnu" } */
+/* Keep labels and directives ('.cfi_startproc', '.cfi_endproc'). */
+/* { dg-final { check-function-bodies "**" "" "" { target { ! ia32 } }
{^\t?\.} } } */
+
+/*
+**bug:
+**.LFB[0-9]+:
+**...
+** leaq tv_cache@tlsld\(%rip\), %rdi
+** call __tls_get_addr@PLT
+** movl \$-1, %edi
+** mov[l|q] %[e|r]ax, %[e|r]bx
+** call val@PLT
+**...
+*/
+
+extern __thread int tv_cache __attribute__ ((visibility("hidden")));
+extern void use_cache (int);
+extern int val (int v);
+
+__attribute__((optimize(2)))
+void
+bug (void)
+{
+ int compared = val(-1);
+
+ if (compared == 0 || (compared > 0 && val(2) == 0))
+ {
+ __builtin_trap();
+ }
+
+ if (compared < 0) {
+ use_cache(tv_cache);
+ return;
+ }
+
+ use_cache(tv_cache);
+ __builtin_trap();
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr121572-1b.c
b/gcc/testsuite/gcc.target/i386/pr121572-1b.c
new file mode 100644
index 00000000000..8a6089109f5
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr121572-1b.c
@@ -0,0 +1,18 @@
+/* { dg-do compile { target *-*-linux* } } */
+/* { dg-options "-O0 -fpic -fplt -mtls-dialect=gnu2" } */
+/* Keep labels and directives ('.cfi_startproc', '.cfi_endproc'). */
+/* { dg-final { check-function-bodies "**" "" "" { target { ! ia32 } }
{^\t?\.} } } */
+
+/*
+**bug:
+**.LFB[0-9]+:
+**...
+** lea[l|q] tv_cache@TLSDESC\(%rip\), %[e|r]ax
+** movl \$-1, %edi
+** call \*tv_cache@TLSCALL\(%[e|r]ax\)
+** mov[l|q] %[e|r]ax, %[e|r]bx
+** call val@PLT
+**...
+*/
+
+#include "pr121572-1a.c"
--
2.50.1
