Backport from FSF mainline: gcc/ * gengtype-lex.l: Add HARD_REG_SET. * expr.c (expand_expr_real_1): Record writes to hard registers. * function.h (rtl_data): Add asm_clobbers. * ira.c (compute_regs_asm_clobbered): Use crtl->asm_clobbers. (ira_setup_eliminable_regset): Remove regs_asm_clobbered. Use crtl->asm_clobbers. gcc/testsuite/ * gcc.target/arm/frame-pointer-1.c: New test. * gcc.target/i386/pr9771-1.c: Move code out of main to allow frame pointer elimination. 2010-07-26 Julian Brown Merge from Sourcery G++ 4.4: 2009-06-23 Kazu Hirata === modified file 'gcc/expr.c' --- old/gcc/expr.c 2010-05-31 14:45:06 +0000 +++ new/gcc/expr.c 2010-08-12 13:51:16 +0000 @@ -8458,6 +8458,19 @@ expand_decl_rtl: gcc_assert (decl_rtl); decl_rtl = copy_rtx (decl_rtl); + /* Record writes to register variables. */ + if (modifier == EXPAND_WRITE && REG_P (decl_rtl) + && REGNO (decl_rtl) < FIRST_PSEUDO_REGISTER) + { + int i = REGNO (decl_rtl); + int nregs = hard_regno_nregs[i][GET_MODE (decl_rtl)]; + while (nregs) + { + SET_HARD_REG_BIT (crtl->asm_clobbers, i); + i++; + nregs--; + } + } /* Ensure variable marked as used even if it doesn't go through a parser. If it hasn't be used yet, write out an external === modified file 'gcc/function.h' --- old/gcc/function.h 2009-11-25 10:55:54 +0000 +++ new/gcc/function.h 2010-08-12 13:51:16 +0000 @@ -25,6 +25,7 @@ #include "tree.h" #include "hashtab.h" #include "vecprim.h" +#include "hard-reg-set.h" /* Stack of pending (incomplete) sequences saved by `start_sequence'. Each element describes one pending sequence. @@ -433,6 +434,12 @@ TREE_NOTHROW (current_function_decl) it is set even for overwritable function where currently compiled version of it is nothrow. */ bool nothrow; + + /* Like regs_ever_live, but 1 if a reg is set or clobbered from an + asm. Unlike regs_ever_live, elements of this array corresponding + to eliminable regs (like the frame pointer) are set if an asm + sets them. */ + HARD_REG_SET asm_clobbers; }; #define return_label (crtl->x_return_label) === modified file 'gcc/gengtype-lex.l' --- old/gcc/gengtype-lex.l 2009-11-21 10:24:25 +0000 +++ new/gcc/gengtype-lex.l 2010-08-12 13:51:16 +0000 @@ -49,7 +49,7 @@ ID [[:alpha:]_][[:alnum:]_]* WS [[:space:]]+ HWS [ \t\r\v\f]* -IWORD short|long|(un)?signed|char|int|HOST_WIDE_INT|HOST_WIDEST_INT|bool|size_t|BOOL_BITFIELD|CPPCHAR_SIGNED_T|ino_t|dev_t +IWORD short|long|(un)?signed|char|int|HOST_WIDE_INT|HOST_WIDEST_INT|bool|size_t|BOOL_BITFIELD|CPPCHAR_SIGNED_T|ino_t|dev_t|HARD_REG_SET ITYPE {IWORD}({WS}{IWORD})* EOID [^[:alnum:]_] === modified file 'gcc/ira.c' --- old/gcc/ira.c 2010-03-31 01:44:10 +0000 +++ new/gcc/ira.c 2010-08-12 13:51:16 +0000 @@ -1385,14 +1385,12 @@ return for_each_rtx (&insn, insn_contains_asm_1, NULL); } -/* Set up regs_asm_clobbered. */ +/* Add register clobbers from asm statements. */ static void -compute_regs_asm_clobbered (char *regs_asm_clobbered) +compute_regs_asm_clobbered (void) { basic_block bb; - memset (regs_asm_clobbered, 0, sizeof (char) * FIRST_PSEUDO_REGISTER); - FOR_EACH_BB (bb) { rtx insn; @@ -1413,7 +1411,7 @@ + hard_regno_nregs[dregno][mode] - 1; for (i = dregno; i <= end; ++i) - regs_asm_clobbered[i] = 1; + SET_HARD_REG_BIT(crtl->asm_clobbers, i); } } } @@ -1425,12 +1423,6 @@ void ira_setup_eliminable_regset (void) { - /* Like regs_ever_live, but 1 if a reg is set or clobbered from an - asm. Unlike regs_ever_live, elements of this array corresponding - to eliminable regs (like the frame pointer) are set if an asm - sets them. */ - char *regs_asm_clobbered - = (char *) alloca (FIRST_PSEUDO_REGISTER * sizeof (char)); #ifdef ELIMINABLE_REGS int i; static const struct {const int from, to; } eliminables[] = ELIMINABLE_REGS; @@ -1454,7 +1446,8 @@ COPY_HARD_REG_SET (ira_no_alloc_regs, no_unit_alloc_regs); CLEAR_HARD_REG_SET (eliminable_regset); - compute_regs_asm_clobbered (regs_asm_clobbered); + compute_regs_asm_clobbered (); + /* Build the regset of all eliminable registers and show we can't use those that we already know won't be eliminated. */ #ifdef ELIMINABLE_REGS @@ -1464,7 +1457,7 @@ = (! targetm.can_eliminate (eliminables[i].from, eliminables[i].to) || (eliminables[i].to == STACK_POINTER_REGNUM && need_fp)); - if (! regs_asm_clobbered[eliminables[i].from]) + if (!TEST_HARD_REG_BIT (crtl->asm_clobbers, eliminables[i].from)) { SET_HARD_REG_BIT (eliminable_regset, eliminables[i].from); @@ -1478,7 +1471,7 @@ df_set_regs_ever_live (eliminables[i].from, true); } #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM - if (! regs_asm_clobbered[HARD_FRAME_POINTER_REGNUM]) + if (!TEST_HARD_REG_BIT (crtl->asm_clobbers, HARD_FRAME_POINTER_REGNUM)) { SET_HARD_REG_BIT (eliminable_regset, HARD_FRAME_POINTER_REGNUM); if (need_fp) @@ -1492,7 +1485,7 @@ #endif #else - if (! regs_asm_clobbered[FRAME_POINTER_REGNUM]) + if (!TEST_HARD_REG_BIT (crtl->asm_clobbers, HARD_FRAME_POINTER_REGNUM)) { SET_HARD_REG_BIT (eliminable_regset, FRAME_POINTER_REGNUM); if (need_fp) === added file 'gcc/testsuite/gcc.target/arm/frame-pointer-1.c' --- old/gcc/testsuite/gcc.target/arm/frame-pointer-1.c 1970-01-01 00:00:00 +0000 +++ new/gcc/testsuite/gcc.target/arm/frame-pointer-1.c 2010-08-12 13:51:16 +0000 @@ -0,0 +1,42 @@ +/* Check local register variables using a register conventionally + used as the frame pointer aren't clobbered under high register pressure. */ +/* { dg-do run } */ +/* { dg-options "-Os -mthumb -fomit-frame-pointer" } */ + +#include + +int global=5; + +void __attribute__((noinline)) foo(int p1, int p2, int p3, int p4) +{ + if (global != 5 || p1 != 1 || p2 != 2 || p3 != 3 || p4 != 4) + abort(); +} + +int __attribute__((noinline)) test(int a, int b, int c, int d) +{ + register unsigned long r __asm__("r7") = 0xdeadbeef; + int e; + + /* ABCD are live after the call which should be enough + to cause r7 to be used if it weren't for the register variable. */ + foo(a,b,c,d); + + e = 0; + __asm__ __volatile__ ("mov %0, %2" + : "=r" (e) + : "0" (e), "r" (r)); + + global = a+b+c+d; + + return e; +} + +int main() +{ + if (test(1, 2, 3, 4) != 0xdeadbeef) + abort(); + if (global != 10) + abort(); + return 0; +} === modified file 'gcc/testsuite/gcc.target/i386/pr9771-1.c' --- old/gcc/testsuite/gcc.target/i386/pr9771-1.c 2007-08-22 08:59:14 +0000 +++ new/gcc/testsuite/gcc.target/i386/pr9771-1.c 2010-08-12 13:51:16 +0000 @@ -28,7 +28,10 @@ *adr = save; } -int main() +/* This must not be inlined becuase main() requires the frame pointer + for stack alignment. */ +void test(void) __attribute__((noinline)); +void test(void) { B = &x; @@ -42,3 +45,9 @@ exit(0); } +int main() +{ + test(); + return 0; + +}