diff options
author | Jeff Law <law@redhat.com> | 2017-01-13 08:42:08 -0700 |
---|---|---|
committer | Jeff Law <law@gcc.gnu.org> | 2017-01-13 08:42:08 -0700 |
commit | d155c6fef06cba08d6ed48b90092c70fa69f8c79 (patch) | |
tree | 4f6529aeda7d903802356f90c11593f8123fef1d | |
parent | 68b36e5903ea260f430e515211a8b169e247f77c (diff) | |
download | gcc-d155c6fef06cba08d6ed48b90092c70fa69f8c79.zip gcc-d155c6fef06cba08d6ed48b90092c70fa69f8c79.tar.gz gcc-d155c6fef06cba08d6ed48b90092c70fa69f8c79.tar.bz2 |
re PR tree-optimization/33562 (aggregate DSE disabled)
PR tree-optimization/33562
PR tree-optimization/61912
PR tree-optimization/77485
* doc/invoke.texi: Document new dse-max-object-size param.
* params.def (PARM_DSE_MAX_OBJECT_SIZE): New PARAM.
* tree-ssa-dse.c: Include params.h.
(dse_store_status): New enum.
(initialize_ao_ref_for_dse): New, partially extracted from
dse_optimize_stmt.
(valid_ao_ref_for_dse, normalize_ref): New.
(setup_live_bytes_from_ref, compute_trims): Likewise.
(clear_bytes_written_by, maybe_trim_complex_store): Likewise.
(maybe_trim_partially_dead_store): Likewise.
(maybe_trim_complex_store): Likewise.
(dse_classify_store): Renamed from dse_possibly_dead_store_p.
Track what bytes live from the original store. Return tri-state
for dead, partially dead or live.
(dse_dom_walker): Add constructor, destructor and new private members.
(delete_dead_call, delete_dead_assignment): New extracted from
dse_optimize_stmt.
(dse_optimize_stmt): Make a member of dse_dom_walker.
Use initialize_ao_ref_for_dse.
PR tree-optimization/33562
PR tree-optimization/61912
PR tree-optimization/77485
* gcc.dg/tree-ssa/complex-4.c: Remove xfail.
* gcc.dg/tree-ssa/complex-5.c: Likewise.
* gcc.dg/tree-ssa/ssa-dse-9.c: Likewise.
* gcc.dg/tree-ssa/ssa-dse-18.c: New test.
* gcc.dg/tree-ssa/ssa-dse-19.c: Likewise.
* gcc.dg/tree-ssa/ssa-dse-20.c: Likewise.
* gcc.dg/tree-ssa/ssa-dse-21.c: Likewise.
From-SVN: r244442
-rw-r--r-- | gcc/ChangeLog | 23 | ||||
-rw-r--r-- | gcc/doc/invoke.texi | 4 | ||||
-rw-r--r-- | gcc/params.def | 5 | ||||
-rw-r--r-- | gcc/testsuite/ChangeLog | 13 | ||||
-rw-r--r-- | gcc/testsuite/gcc.dg/tree-ssa/complex-4.c | 2 | ||||
-rw-r--r-- | gcc/testsuite/gcc.dg/tree-ssa/complex-5.c | 2 | ||||
-rw-r--r-- | gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-18.c | 15 | ||||
-rw-r--r-- | gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-19.c | 15 | ||||
-rw-r--r-- | gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-20.c | 13 | ||||
-rw-r--r-- | gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-21.c | 12 | ||||
-rw-r--r-- | gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-9.c | 2 | ||||
-rw-r--r-- | gcc/tree-ssa-dse.c | 430 |
12 files changed, 462 insertions, 74 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index d6b95eb..3cb1a60 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,5 +1,28 @@ 2017-01-13 Jeff Law <law@redhat.com> + PR tree-optimization/33562 + PR tree-optimization/61912 + PR tree-optimization/77485 + * doc/invoke.texi: Document new dse-max-object-size param. + * params.def (PARM_DSE_MAX_OBJECT_SIZE): New PARAM. + * tree-ssa-dse.c: Include params.h. + (dse_store_status): New enum. + (initialize_ao_ref_for_dse): New, partially extracted from + dse_optimize_stmt. + (valid_ao_ref_for_dse, normalize_ref): New. + (setup_live_bytes_from_ref, compute_trims): Likewise. + (clear_bytes_written_by, maybe_trim_complex_store): Likewise. + (maybe_trim_partially_dead_store): Likewise. + (maybe_trim_complex_store): Likewise. + (dse_classify_store): Renamed from dse_possibly_dead_store_p. + Track what bytes live from the original store. Return tri-state + for dead, partially dead or live. + (dse_dom_walker): Add constructor, destructor and new private members. + (delete_dead_call, delete_dead_assignment): New extracted from + dse_optimize_stmt. + (dse_optimize_stmt): Make a member of dse_dom_walker. + Use initialize_ao_ref_for_dse. + PR tree-optimization/33562 PR tree-optimization/61912 PR tree-optimization/77485 diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 69f0adb..99f193e 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -9880,6 +9880,10 @@ when adding a new one. @item avg-loop-niter Average number of iterations of a loop. +@item dse-max-object-size +Maximum size (in bytes) of objects tracked bytewise by dead store elimination. +Larger values may result in larger compilation times. + @item scev-max-expr-size Bound on size of expressions used in the scalar evolutions analyzer. Large expressions slow the analyzer. diff --git a/gcc/params.def b/gcc/params.def index 6c6cde2..e598d34 100644 --- a/gcc/params.def +++ b/gcc/params.def @@ -532,6 +532,11 @@ DEFPARAM(PARAM_AVG_LOOP_NITER, "Average number of iterations of a loop.", 10, 1, 0) +DEFPARAM(PARAM_DSE_MAX_OBJECT_SIZE, + "dse-max-object-size", + "Maximum size (in bytes) of objects tracked bytewise by dead store elimination.", + 256, 0, 0) + DEFPARAM(PARAM_SCEV_MAX_EXPR_SIZE, "scev-max-expr-size", "Bound on size of expressions used in the scalar evolutions analyzer.", diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 33c5955..edee5a4 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,16 @@ +2017-01-13 Jeff Law <law@redhat.com> + + PR tree-optimization/33562 + PR tree-optimization/61912 + PR tree-optimization/77485 + * gcc.dg/tree-ssa/complex-4.c: Remove xfail. + * gcc.dg/tree-ssa/complex-5.c: Likewise. + * gcc.dg/tree-ssa/ssa-dse-9.c: Likewise. + * gcc.dg/tree-ssa/ssa-dse-18.c: New test. + * gcc.dg/tree-ssa/ssa-dse-19.c: Likewise. + * gcc.dg/tree-ssa/ssa-dse-20.c: Likewise. + * gcc.dg/tree-ssa/ssa-dse-21.c: Likewise. + 2017-01-13 Martin Liska <mliska@suse.cz> PR ipa/79043 diff --git a/gcc/testsuite/gcc.dg/tree-ssa/complex-4.c b/gcc/testsuite/gcc.dg/tree-ssa/complex-4.c index 87a2638..3155741 100644 --- a/gcc/testsuite/gcc.dg/tree-ssa/complex-4.c +++ b/gcc/testsuite/gcc.dg/tree-ssa/complex-4.c @@ -10,4 +10,4 @@ int f(void) return g(&t); } -/* { dg-final { scan-tree-dump-times "__complex__" 0 "optimized" { xfail *-*-* } } } */ +/* { dg-final { scan-tree-dump-times "__complex__" 0 "optimized" } } */ diff --git a/gcc/testsuite/gcc.dg/tree-ssa/complex-5.c b/gcc/testsuite/gcc.dg/tree-ssa/complex-5.c index e2cd403..e6d027f 100644 --- a/gcc/testsuite/gcc.dg/tree-ssa/complex-5.c +++ b/gcc/testsuite/gcc.dg/tree-ssa/complex-5.c @@ -8,4 +8,4 @@ int f(void) __imag__ t = 2; } -/* { dg-final { scan-tree-dump-times "__complex__" 0 "optimized" { xfail *-*-* } } } */ +/* { dg-final { scan-tree-dump-times "__complex__" 0 "optimized" } } */ diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-18.c b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-18.c new file mode 100644 index 0000000..92b2df8 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-18.c @@ -0,0 +1,15 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fdump-tree-optimized" } */ +int g(_Complex int*); +int f(void) +{ + _Complex int t = 0; + int i, j; + __imag__ t += 2; + return g(&t); +} + + +/* { dg-final { scan-tree-dump-times "__complex__" 0 "optimized" } } */ +/* { dg-final { scan-tree-dump-times "REALPART_EXPR" 1 "optimized" } } */ +/* { dg-final { scan-tree-dump-times "IMAGPART_EXPR" 1 "optimized" } } */ diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-19.c b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-19.c new file mode 100644 index 0000000..718b746 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-19.c @@ -0,0 +1,15 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fdump-tree-optimized" } */ +int g(_Complex int*); +int f(void) +{ + _Complex int t = 0; + int i, j; + __real__ t += 2; + return g(&t); +} + + +/* { dg-final { scan-tree-dump-times "__complex__" 0 "optimized" } } */ +/* { dg-final { scan-tree-dump-times "REALPART_EXPR" 1 "optimized" } } */ +/* { dg-final { scan-tree-dump-times "IMAGPART_EXPR" 1 "optimized" } } */ diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-20.c b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-20.c new file mode 100644 index 0000000..4e14d9b --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-20.c @@ -0,0 +1,13 @@ +/* { dg-do compile } */ +/* { dg-options "-O1 -fno-tree-dce -fdump-tree-optimized" } */ +_Complex int t = 0; +int f(void) +{ + t = 0; + __imag__ t = 2; +} + +/* { dg-final { scan-tree-dump-times "__complex__" 0 "optimized" } } */ +/* { dg-final { scan-tree-dump-times "REALPART_EXPR" 1 "optimized" } } */ +/* { dg-final { scan-tree-dump-times "IMAGPART_EXPR" 1 "optimized" } } */ + diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-21.c b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-21.c new file mode 100644 index 0000000..d1e0b85 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-21.c @@ -0,0 +1,12 @@ +/* { dg-do compile } */ +/* { dg-options "-O1 -fno-tree-dce -fdump-tree-optimized" } */ +_Complex int t = 0; +int f(void) +{ + t = 0; + __real__ t = 2; +} + +/* { dg-final { scan-tree-dump-times "__complex__" 0 "optimized" } } */ +/* { dg-final { scan-tree-dump-times "REALPART_EXPR" 1 "optimized" } } */ +/* { dg-final { scan-tree-dump-times "IMAGPART_EXPR" 1 "optimized" } } */ diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-9.c b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-9.c index 594c20c..ae48ddd 100644 --- a/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-9.c +++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-9.c @@ -11,4 +11,4 @@ foo () } /* We should eliminate the first assignment. */ -/* { dg-final { scan-tree-dump-times "VDEF" 2 "dse1" { xfail *-*-* } } } */ +/* { dg-final { scan-tree-dump-times "VDEF" 2 "dse1" } } */ diff --git a/gcc/tree-ssa-dse.c b/gcc/tree-ssa-dse.c index 76cc27d..daaa99c 100644 --- a/gcc/tree-ssa-dse.c +++ b/gcc/tree-ssa-dse.c @@ -33,6 +33,7 @@ along with GCC; see the file COPYING3. If not see #include "tree-dfa.h" #include "domwalk.h" #include "tree-cfgcleanup.h" +#include "params.h" /* This file implements dead store elimination. @@ -68,14 +69,241 @@ along with GCC; see the file COPYING3. If not see remove their dead edges eventually. */ static bitmap need_eh_cleanup; +/* Return value from dse_classify_store */ +enum dse_store_status +{ + DSE_STORE_LIVE, + DSE_STORE_MAYBE_PARTIAL_DEAD, + DSE_STORE_DEAD +}; + +/* STMT is a statement that may write into memory. Analyze it and + initialize WRITE to describe how STMT affects memory. + + Return TRUE if the the statement was analyzed, FALSE otherwise. + + It is always safe to return FALSE. But typically better optimziation + can be achieved by analyzing more statements. */ + +static bool +initialize_ao_ref_for_dse (gimple *stmt, ao_ref *write) +{ + /* It's advantageous to handle certain mem* functions. */ + if (gimple_call_builtin_p (stmt, BUILT_IN_NORMAL)) + { + switch (DECL_FUNCTION_CODE (gimple_call_fndecl (stmt))) + { + case BUILT_IN_MEMCPY: + case BUILT_IN_MEMMOVE: + case BUILT_IN_MEMSET: + { + tree size = NULL_TREE; + if (gimple_call_num_args (stmt) == 3) + size = gimple_call_arg (stmt, 2); + tree ptr = gimple_call_arg (stmt, 0); + ao_ref_init_from_ptr_and_size (write, ptr, size); + return true; + } + default: + break; + } + } + else if (is_gimple_assign (stmt)) + { + ao_ref_init (write, gimple_assign_lhs (stmt)); + return true; + } + return false; +} + +/* Given REF from the the alias oracle, return TRUE if it is a valid + memory reference for dead store elimination, false otherwise. + + In particular, the reference must have a known base, known maximum + size, start at a byte offset and have a size that is one or more + bytes. */ + +static bool +valid_ao_ref_for_dse (ao_ref *ref) +{ + return (ao_ref_base (ref) + && ref->max_size != -1 + && (ref->offset % BITS_PER_UNIT) == 0 + && (ref->size % BITS_PER_UNIT) == 0 + && (ref->size != -1)); +} + +/* Normalize COPY (an ao_ref) relative to REF. Essentially when we are + done COPY will only refer bytes found within REF. + + We have already verified that COPY intersects at least one + byte with REF. */ + +static void +normalize_ref (ao_ref *copy, ao_ref *ref) +{ + /* If COPY starts before REF, then reset the beginning of + COPY to match REF and decrease the size of COPY by the + number of bytes removed from COPY. */ + if (copy->offset < ref->offset) + { + copy->size -= (ref->offset - copy->offset); + copy->offset = ref->offset; + } + + /* If COPY extends beyond REF, chop off its size appropriately. */ + if (copy->offset + copy->size > ref->offset + ref->size) + copy->size -= (copy->offset + copy->size - (ref->offset + ref->size)); +} + +/* Clear any bytes written by STMT from the bitmap LIVE_BYTES. The base + address written by STMT must match the one found in REF, which must + have its base address previously initialized. + + This routine must be conservative. If we don't know the offset or + actual size written, assume nothing was written. */ + +static void +clear_bytes_written_by (sbitmap live_bytes, gimple *stmt, ao_ref *ref) +{ + ao_ref write; + if (!initialize_ao_ref_for_dse (stmt, &write)) + return; + + /* Verify we have the same base memory address, the write + has a known size and overlaps with REF. */ + if (valid_ao_ref_for_dse (&write) + && write.base == ref->base + && write.size == write.max_size + && ((write.offset < ref->offset + && write.offset + write.size > ref->offset) + || (write.offset >= ref->offset + && write.offset < ref->offset + ref->size))) + { + normalize_ref (&write, ref); + bitmap_clear_range (live_bytes, + (write.offset - ref->offset) / BITS_PER_UNIT, + write.size / BITS_PER_UNIT); + } +} + +/* REF is a memory write. Extract relevant information from it and + initialize the LIVE_BYTES bitmap. If successful, return TRUE. + Otherwise return FALSE. */ + +static bool +setup_live_bytes_from_ref (ao_ref *ref, sbitmap live_bytes) +{ + if (valid_ao_ref_for_dse (ref) + && (ref->size / BITS_PER_UNIT + <= PARAM_VALUE (PARAM_DSE_MAX_OBJECT_SIZE))) + { + bitmap_clear (live_bytes); + bitmap_set_range (live_bytes, 0, ref->size / BITS_PER_UNIT); + return true; + } + return false; +} + +/* Compute the number of elements that we can trim from the head and + tail of ORIG resulting in a bitmap that is a superset of LIVE. + + Store the number of elements trimmed from the head and tail in + TRIM_HEAD and TRIM_TAIL. */ + +static void +compute_trims (ao_ref *ref, sbitmap live, int *trim_head, int *trim_tail) +{ + /* We use sbitmaps biased such that ref->offset is bit zero and the bitmap + extends through ref->size. So we know that in the original bitmap + bits 0..ref->size were true. We don't actually need the bitmap, just + the REF to compute the trims. */ + + /* Now identify how much, if any of the tail we can chop off. */ + *trim_tail = 0; + int last_orig = (ref->size / BITS_PER_UNIT) - 1; + int last_live = bitmap_last_set_bit (live); + *trim_tail = (last_orig - last_live) & ~0x1; + + /* Identify how much, if any of the head we can chop off. */ + int first_orig = 0; + int first_live = bitmap_first_set_bit (live); + *trim_head = (first_live - first_orig) & ~0x1; +} + +/* STMT initializes an object from COMPLEX_CST where one or more of the + bytes written may be dead stores. REF is a representation of the + memory written. LIVE is the bitmap of stores that are actually live. + + Attempt to rewrite STMT so that only the real or imaginary part of + the object is actually stored. */ + +static void +maybe_trim_complex_store (ao_ref *ref, sbitmap live, gimple *stmt) +{ + int trim_head, trim_tail; + compute_trims (ref, live, &trim_head, &trim_tail); + + /* The amount of data trimmed from the head or tail must be at + least half the size of the object to ensure we're trimming + the entire real or imaginary half. By writing things this + way we avoid more O(n) bitmap operations. */ + if (trim_tail * 2 >= ref->size / BITS_PER_UNIT) + { + /* TREE_REALPART is live */ + tree x = TREE_REALPART (gimple_assign_rhs1 (stmt)); + tree y = gimple_assign_lhs (stmt); + y = build1 (REALPART_EXPR, TREE_TYPE (x), y); + gimple_assign_set_lhs (stmt, y); + gimple_assign_set_rhs1 (stmt, x); + } + else if (trim_head * 2 >= ref->size / BITS_PER_UNIT) + { + /* TREE_IMAGPART is live */ + tree x = TREE_IMAGPART (gimple_assign_rhs1 (stmt)); + tree y = gimple_assign_lhs (stmt); + y = build1 (IMAGPART_EXPR, TREE_TYPE (x), y); + gimple_assign_set_lhs (stmt, y); + gimple_assign_set_rhs1 (stmt, x); + } + + /* Other cases indicate parts of both the real and imag subobjects + are live. We do not try to optimize those cases. */ +} + +/* STMT is a memory write where one or more bytes written are dead + stores. ORIG is the bitmap of bytes stored by STMT. LIVE is the + bitmap of stores that are actually live. + + Attempt to rewrite STMT so that it writes fewer memory locations. Right + now we only support trimming at the start or end of the memory region. + It's not clear how much there is to be gained by trimming from the middle + of the region. */ + +static void +maybe_trim_partially_dead_store (ao_ref *ref, sbitmap live, gimple *stmt) +{ + if (is_gimple_assign (stmt)) + { + switch (gimple_assign_rhs_code (stmt)) + { + case COMPLEX_CST: + maybe_trim_complex_store (ref, live, stmt); + break; + default: + break; + } + } +} /* A helper of dse_optimize_stmt. Given a GIMPLE_ASSIGN in STMT that writes to REF, find a candidate statement *USE_STMT that may prove STMT to be dead. Return TRUE if the above conditions are met, otherwise FALSE. */ -static bool -dse_possible_dead_store_p (ao_ref *ref, gimple *stmt, gimple **use_stmt) +static dse_store_status +dse_classify_store (ao_ref *ref, gimple *stmt, gimple **use_stmt, + bool byte_tracking_enabled, sbitmap live_bytes) { gimple *temp; unsigned cnt = 0; @@ -97,7 +325,7 @@ dse_possible_dead_store_p (ao_ref *ref, gimple *stmt, gimple **use_stmt) /* Limit stmt walking to be linear in the number of possibly dead stores. */ if (++cnt > 256) - return false; + return DSE_STORE_LIVE; if (gimple_code (temp) == GIMPLE_PHI) defvar = PHI_RESULT (temp); @@ -135,7 +363,7 @@ dse_possible_dead_store_p (ao_ref *ref, gimple *stmt, gimple **use_stmt) fail = true; BREAK_FROM_IMM_USE_STMT (ui); } - /* Do not consider the PHI as use if it dominates the + /* Do not consider the PHI as use if it dominates the stmt defining the virtual operand we are processing, we have processed it already in this case. */ if (gimple_bb (defvar_def) != gimple_bb (use_stmt) @@ -164,7 +392,13 @@ dse_possible_dead_store_p (ao_ref *ref, gimple *stmt, gimple **use_stmt) } if (fail) - return false; + { + /* STMT might be partially dead and we may be able to reduce + how many memory locations it stores into. */ + if (byte_tracking_enabled && !gimple_clobber_p (stmt)) + return DSE_STORE_MAYBE_PARTIAL_DEAD; + return DSE_STORE_LIVE; + } /* If we didn't find any definition this means the store is dead if it isn't a store to global reachable memory. In this case @@ -172,20 +406,101 @@ dse_possible_dead_store_p (ao_ref *ref, gimple *stmt, gimple **use_stmt) if (!temp) { if (ref_may_alias_global_p (ref)) - return false; + return DSE_STORE_LIVE; temp = stmt; break; } + + if (byte_tracking_enabled && temp) + clear_bytes_written_by (live_bytes, temp, ref); } - /* Continue walking until we reach a kill. */ - while (!stmt_kills_ref_p (temp, ref)); + /* Continue walking until we reach a full kill as a single statement + or there are no more live bytes. */ + while (!stmt_kills_ref_p (temp, ref) + && !(byte_tracking_enabled && bitmap_empty_p (live_bytes))); *use_stmt = temp; + return DSE_STORE_DEAD; +} + + +class dse_dom_walker : public dom_walker +{ +public: + dse_dom_walker (cdi_direction direction) + : dom_walker (direction), m_byte_tracking_enabled (false) + + { m_live_bytes = sbitmap_alloc (PARAM_VALUE (PARAM_DSE_MAX_OBJECT_SIZE)); } - return true; + ~dse_dom_walker () { sbitmap_free (m_live_bytes); } + + virtual edge before_dom_children (basic_block); + +private: + sbitmap m_live_bytes; + bool m_byte_tracking_enabled; + void dse_optimize_stmt (gimple_stmt_iterator *); +}; + +/* Delete a dead call STMT, which is mem* call of some kind. */ +static void +delete_dead_call (gimple *stmt) +{ + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, " Deleted dead call: "); + print_gimple_stmt (dump_file, stmt, dump_flags, 0); + fprintf (dump_file, "\n"); + } + + tree lhs = gimple_call_lhs (stmt); + gimple_stmt_iterator gsi = gsi_for_stmt (stmt); + if (lhs) + { + tree ptr = gimple_call_arg (stmt, 0); + gimple *new_stmt = gimple_build_assign (lhs, ptr); + unlink_stmt_vdef (stmt); + if (gsi_replace (&gsi, new_stmt, true)) + bitmap_set_bit (need_eh_cleanup, gimple_bb (stmt)->index); + } + else + { + /* Then we need to fix the operand of the consuming stmt. */ + unlink_stmt_vdef (stmt); + + /* Remove the dead store. */ + if (gsi_remove (&gsi, true)) + bitmap_set_bit (need_eh_cleanup, gimple_bb (stmt)->index); + release_defs (stmt); + } } +/* Delete a dead store STMT, which is a gimple assignment. */ + +static void +delete_dead_assignment (gimple *stmt) +{ + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, " Deleted dead store: "); + print_gimple_stmt (dump_file, stmt, dump_flags, 0); + fprintf (dump_file, "\n"); + } + + /* Then we need to fix the operand of the consuming stmt. */ + unlink_stmt_vdef (stmt); + + /* Remove the dead store. */ + gimple_stmt_iterator gsi = gsi_for_stmt (stmt); + basic_block bb = gimple_bb (stmt); + if (gsi_remove (&gsi, true)) + bitmap_set_bit (need_eh_cleanup, bb->index); + + /* And release any SSA_NAMEs set in this statement back to the + SSA_NAME manager. */ + release_defs (stmt); +} /* Attempt to eliminate dead stores in the statement referenced by BSI. @@ -198,8 +513,8 @@ dse_possible_dead_store_p (ao_ref *ref, gimple *stmt, gimple **use_stmt) is used precisely once by a later store to the same location which post dominates the first store, then the first store is dead. */ -static void -dse_optimize_stmt (gimple_stmt_iterator *gsi) +void +dse_dom_walker::dse_optimize_stmt (gimple_stmt_iterator *gsi) { gimple *stmt = gsi_stmt (*gsi); @@ -214,6 +529,10 @@ dse_optimize_stmt (gimple_stmt_iterator *gsi) || TREE_CODE (gimple_assign_lhs (stmt)) != MEM_REF)) return; + ao_ref ref; + if (!initialize_ao_ref_for_dse (stmt, &ref)) + return; + /* We know we have virtual definitions. We can handle assignments and some builtin calls. */ if (gimple_call_builtin_p (stmt, BUILT_IN_NORMAL)) @@ -225,42 +544,26 @@ dse_optimize_stmt (gimple_stmt_iterator *gsi) case BUILT_IN_MEMSET: { gimple *use_stmt; - ao_ref ref; - tree size = NULL_TREE; - if (gimple_call_num_args (stmt) == 3) - size = gimple_call_arg (stmt, 2); - tree ptr = gimple_call_arg (stmt, 0); - ao_ref_init_from_ptr_and_size (&ref, ptr, size); - if (!dse_possible_dead_store_p (&ref, stmt, &use_stmt)) + enum dse_store_status store_status; + m_byte_tracking_enabled + = setup_live_bytes_from_ref (&ref, m_live_bytes); + store_status = dse_classify_store (&ref, stmt, &use_stmt, + m_byte_tracking_enabled, + m_live_bytes); + if (store_status == DSE_STORE_LIVE) return; - if (dump_file && (dump_flags & TDF_DETAILS)) - { - fprintf (dump_file, " Deleted dead call: "); - print_gimple_stmt (dump_file, gsi_stmt (*gsi), dump_flags, 0); - fprintf (dump_file, "\n"); - } - - tree lhs = gimple_call_lhs (stmt); - if (lhs) + if (store_status == DSE_STORE_MAYBE_PARTIAL_DEAD) { - gimple *new_stmt = gimple_build_assign (lhs, ptr); - unlink_stmt_vdef (stmt); - if (gsi_replace (gsi, new_stmt, true)) - bitmap_set_bit (need_eh_cleanup, gimple_bb (stmt)->index); + maybe_trim_partially_dead_store (&ref, m_live_bytes, stmt); + return; } - else - { - /* Then we need to fix the operand of the consuming stmt. */ - unlink_stmt_vdef (stmt); - /* Remove the dead store. */ - if (gsi_remove (gsi, true)) - bitmap_set_bit (need_eh_cleanup, gimple_bb (stmt)->index); - release_defs (stmt); - } - break; + if (store_status == DSE_STORE_DEAD) + delete_dead_call (stmt); + return; } + default: return; } @@ -276,10 +579,20 @@ dse_optimize_stmt (gimple_stmt_iterator *gsi) use_stmt = stmt; else { - ao_ref ref; - ao_ref_init (&ref, gimple_assign_lhs (stmt)); - if (!dse_possible_dead_store_p (&ref, stmt, &use_stmt)) + m_byte_tracking_enabled + = setup_live_bytes_from_ref (&ref, m_live_bytes); + enum dse_store_status store_status; + store_status = dse_classify_store (&ref, stmt, &use_stmt, + m_byte_tracking_enabled, + m_live_bytes); + if (store_status == DSE_STORE_LIVE) return; + + if (store_status == DSE_STORE_MAYBE_PARTIAL_DEAD) + { + maybe_trim_partially_dead_store (&ref, m_live_bytes, stmt); + return; + } } /* Now we know that use_stmt kills the LHS of stmt. */ @@ -290,35 +603,10 @@ dse_optimize_stmt (gimple_stmt_iterator *gsi) && !gimple_clobber_p (use_stmt)) return; - if (dump_file && (dump_flags & TDF_DETAILS)) - { - fprintf (dump_file, " Deleted dead store: "); - print_gimple_stmt (dump_file, gsi_stmt (*gsi), dump_flags, 0); - fprintf (dump_file, "\n"); - } - - /* Then we need to fix the operand of the consuming stmt. */ - unlink_stmt_vdef (stmt); - - /* Remove the dead store. */ - basic_block bb = gimple_bb (stmt); - if (gsi_remove (gsi, true)) - bitmap_set_bit (need_eh_cleanup, bb->index); - - /* And release any SSA_NAMEs set in this statement back to the - SSA_NAME manager. */ - release_defs (stmt); + delete_dead_assignment (stmt); } } -class dse_dom_walker : public dom_walker -{ -public: - dse_dom_walker (cdi_direction direction) : dom_walker (direction) {} - - virtual edge before_dom_children (basic_block); -}; - edge dse_dom_walker::before_dom_children (basic_block bb) { @@ -391,7 +679,7 @@ pass_dse::execute (function *fun) } BITMAP_FREE (need_eh_cleanup); - + /* For now, just wipe the post-dominator information. */ free_dominance_info (CDI_POST_DOMINATORS); return 0; |