diff options
| -rw-r--r-- | gcc/ChangeLog | 8 | ||||
| -rw-r--r-- | gcc/Makefile.in | 2 | ||||
| -rw-r--r-- | gcc/tree-ssa-ccp.c | 60 |
3 files changed, 69 insertions, 1 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index da9fec0088d..ad45eb4c96e 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,11 @@ +2011-08-31 Tom de Vries <tom@codesourcery.com> + + PR middle-end/43513 + * Makefile.in (tree-ssa-ccp.o): Add $(PARAMS_H) to rule. + * tree-ssa-ccp.c (params.h): Include. + (fold_builtin_alloca_for_var): New function. + (ccp_fold_stmt): Use fold_builtin_alloca_for_var. + 2011-08-30 Uros Bizjak <ubizjak@gmail.com> * config/i386/i386.c (ix86_valid_target_attribute_inner_p): diff --git a/gcc/Makefile.in b/gcc/Makefile.in index 8679e7b961e..d5caba6c7f7 100644 --- a/gcc/Makefile.in +++ b/gcc/Makefile.in @@ -3154,7 +3154,7 @@ tree-call-cdce.o : tree-call-cdce.c $(CONFIG_H) $(SYSTEM_H) $(TREE_H) \ tree-ssa-ccp.o : tree-ssa-ccp.c $(TREE_FLOW_H) $(CONFIG_H) \ $(SYSTEM_H) $(TREE_H) $(TM_P_H) $(EXPR_H) output.h \ $(DIAGNOSTIC_H) $(FUNCTION_H) $(TIMEVAR_H) $(TM_H) coretypes.h \ - $(TREE_DUMP_H) $(BASIC_BLOCK_H) $(TREE_PASS_H) langhooks.h \ + $(TREE_DUMP_H) $(BASIC_BLOCK_H) $(TREE_PASS_H) langhooks.h $(PARAMS_H) \ tree-ssa-propagate.h value-prof.h $(FLAGS_H) $(TARGET_H) $(DIAGNOSTIC_CORE_H) \ $(DBGCNT_H) tree-pretty-print.h gimple-pretty-print.h gimple-fold.h tree-sra.o : tree-sra.c $(CONFIG_H) $(SYSTEM_H) coretypes.h alloc-pool.h \ diff --git a/gcc/tree-ssa-ccp.c b/gcc/tree-ssa-ccp.c index 55a504ee52d..007e17dd8b6 100644 --- a/gcc/tree-ssa-ccp.c +++ b/gcc/tree-ssa-ccp.c @@ -133,6 +133,7 @@ along with GCC; see the file COPYING3. If not see #include "diagnostic-core.h" #include "dbgcnt.h" #include "gimple-fold.h" +#include "params.h" /* Possible lattice values. */ @@ -1684,6 +1685,51 @@ evaluate_stmt (gimple stmt) return val; } +/* Detects a vla-related alloca with a constant argument. Declares fixed-size + array and return the address, if found, otherwise returns NULL_TREE. */ + +static tree +fold_builtin_alloca_for_var (gimple stmt) +{ + unsigned HOST_WIDE_INT size, threshold, n_elem; + tree lhs, arg, block, var, elem_type, array_type; + unsigned int align; + + /* Get lhs. */ + lhs = gimple_call_lhs (stmt); + if (lhs == NULL_TREE) + return NULL_TREE; + + /* Detect constant argument. */ + arg = get_constant_value (gimple_call_arg (stmt, 0)); + if (arg == NULL_TREE || TREE_CODE (arg) != INTEGER_CST + || !host_integerp (arg, 1)) + return NULL_TREE; + size = TREE_INT_CST_LOW (arg); + + /* Heuristic: don't fold large vlas. */ + threshold = (unsigned HOST_WIDE_INT)PARAM_VALUE (PARAM_LARGE_STACK_FRAME); + /* In case a vla is declared at function scope, it has the same lifetime as a + declared array, so we allow a larger size. */ + block = gimple_block (stmt); + if (!(cfun->after_inlining + && TREE_CODE (BLOCK_SUPERCONTEXT (block)) == FUNCTION_DECL)) + threshold /= 10; + if (size > threshold) + return NULL_TREE; + + /* Declare array. */ + elem_type = build_nonstandard_integer_type (BITS_PER_UNIT, 1); + n_elem = size * 8 / BITS_PER_UNIT; + align = MIN (size * 8, BIGGEST_ALIGNMENT); + array_type = build_array_type_nelts (elem_type, n_elem); + var = create_tmp_var (array_type, NULL); + DECL_ALIGN (var) = align; + + /* Fold alloca to the address of the array. */ + return fold_convert (TREE_TYPE (lhs), build_fold_addr_expr (var)); +} + /* Fold the stmt at *GSI with CCP specific information that propagating and regular folding does not catch. */ @@ -1752,6 +1798,20 @@ ccp_fold_stmt (gimple_stmt_iterator *gsi) if (gimple_call_internal_p (stmt)) return false; + /* The heuristic of fold_builtin_alloca_for_var differs before and after + inlining, so we don't require the arg to be changed into a constant + for folding, but just to be constant. */ + if (gimple_call_alloca_for_var_p (stmt)) + { + tree new_rhs = fold_builtin_alloca_for_var (stmt); + bool res; + if (new_rhs == NULL_TREE) + return false; + res = update_call_from_tree (gsi, new_rhs); + gcc_assert (res); + return true; + } + /* Propagate into the call arguments. Compared to replace_uses_in this can use the argument slot types for type verification instead of the current argument type. We also can safely |
