Hi,
this is updated patch which adds -fmalloc-dce flag to control malloc/free
removal. I ended up copying what -fallocation-dse does so -fmalloc-dce=1
enables malloc/free removal provided return value is unused otherwise and
-fmalloc-dce=2 allows additional NULL pointer checks which it folds to non-NULL
direction.
I also added compensation for the gcc.dg/analyzer/pr101837.c testcase and
added testcase that std::nothrow variant of operator new is now optimized way.
With the -fmalloc-dce=n I can also add a level which emits runtime check for
half
of address space and calloc overflow if it seems useful, but perhaps
incrementally. Adding size parameter tracking is not that hard (I posted WIP
patch for that).
Bootstrapped/regtested x86_64-linux, OK?
* common.opt: Add -fmalloc-dce.
* doc/invoke.texi: Document it; also add missing -flifetime-dse entry.
* tree-ssa-dce.cc (is_removable_allocation_p): Break out from
...
(mark_stmt_if_obviously_necessary): ... here; also check that
operator new satisfies gimple_call_from_new_or_delete.
(checks_return_value_of_removable_allocation_p): New Function.
(mark_all_reaching_defs_necessary_1): add missing case ofr
STRDUP and STRNDUP
(propagate_necessity): Use is_removable_allocation_p and
checks_return_value_of_removable_allocation_p.
(eliminate_unnecessary_stmts): Update conditionals that use
removed allocation; use is_removable_allocation_p.
gcc/testsuite/ChangeLog:
* g++.dg/cdce3.C: Disable allocation dce.
* g++.dg/tree-ssa/pr19476-1.C: Likewise.
* g++.dg/tree-ssa/pr19476-2.C: Likewise.
* g++.dg/tree-ssa/pr19476-3.C: Likewise.
* g++.dg/tree-ssa/pr19476-4.C: Likewise.
* gcc.dg/analyzer/pr101837.c: Disable malloc dce.
* gcc.dg/tree-ssa/pr19831-3.c: Update.
* gfortran.dg/pr68078.f90: Disable malloc DCE.
* g++.dg/tree-ssa/dce-1.C: New test.
diff --git a/gcc/common.opt b/gcc/common.opt
index 0b1f1ec26e1..1a79f71789e 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -2282,6 +2282,13 @@ fmax-errors=
Common Joined RejectNegative UInteger Var(flag_max_errors)
-fmax-errors=<number> Maximum number of errors to report.
+fmalloc-dce
+Common Var(flag_malloc_dce,2) Init(2) Optimization
+Allow removal of malloc and free pairs when allocated block is unused
+
+fmalloc-dce=
+Common Joined RejectNegative UInteger Var(flag_malloc_dse) Optimization
IntegerRange(0, 2)
+
fmem-report
Common Var(mem_report)
Report on permanent memory allocation.
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 7146163d66d..ba69ebe591c 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -585,7 +585,7 @@ Objective-C and Objective-C++ Dialects}.
-fipa-bit-cp -fipa-vrp -fipa-pta -fipa-profile -fipa-pure-const
-fipa-reference -fipa-reference-addressable
-fipa-stack-alignment -fipa-icf -fira-algorithm=@var{algorithm}
--flate-combine-instructions -flive-patching=@var{level}
+-flate-combine-instructions -flifetime-dse -flive-patching=@var{level}
-fira-region=@var{region} -fira-hoist-pressure
-fira-loop-pressure -fno-ira-share-save-slots
-fno-ira-share-spill-slots
@@ -595,7 +595,7 @@ Objective-C and Objective-C++ Dialects}.
-floop-block -floop-interchange -floop-strip-mine
-floop-unroll-and-jam -floop-nest-optimize
-floop-parallelize-all -flra-remat -flto -flto-compression-level
--flto-partition=@var{alg} -fmerge-all-constants
+-flto-partition=@var{alg} -fmalloc-dce -fmerge-all-constants
-fmerge-constants -fmodulo-sched -fmodulo-sched-allow-regmoves
-fmove-loop-invariants -fmove-loop-stores -fno-branch-count-reg
-fno-defer-pop -fno-fp-int-builtin-inexact -fno-function-cse
@@ -14568,8 +14568,12 @@ affected by @option{-flimit-function-alignment}
@opindex fno-allocation-dce
+@opindex fallocation-dce
@item -fno-allocation-dce
-Do not remove unused C++ allocations in dead code elimination.
+Do not remove unused C++ allocations (using operator @code{new} and operator
@code{delete})
+in dead code elimination.
+
+See also @option{-fmalloc-dce}.
@opindex fallow-store-data-races
@item -fallow-store-data-races
@@ -15442,6 +15446,18 @@ number of iterations).
Enabled by @option{-O3}, @option{-fprofile-use}, and @option{-fauto-profile}.
+@opindex fno-malloc-dce
+@opindex fmalloc-dce
+@item -fmalloc-dce
+Control whether @code{malloc} (and its variatns such as @code{calloc} or
+@code{strdup}), can be optimized away provided its return value is only used
+as a parameter of @code{free} call or compared with @code{NULL}. If
+@option{-fmalloc-dce=1} is used, only calls to @code{free} are allowed while
+with @option{-fmalloc-dce=2} also comparsions with @code{NULL} pointer are
+considered safe to remove.
+
+The default is @option{-fmalloc-dce=2}. See also @option{-fallocation-dce}.
+
@opindex fmove-loop-invariants
@item -fmove-loop-invariants
Enables the loop invariant motion pass in the RTL loop optimizer. Enabled
diff --git a/gcc/testsuite/g++.dg/cdce3.C b/gcc/testsuite/g++.dg/cdce3.C
index 2543317f6b2..9aecf58a8b8 100644
--- a/gcc/testsuite/g++.dg/cdce3.C
+++ b/gcc/testsuite/g++.dg/cdce3.C
@@ -1,6 +1,6 @@
/* { dg-do run } */
/* { dg-require-effective-target c99_runtime } */
-/* { dg-options "-O2 -fmath-errno -fdump-tree-cdce-details -lm" } */
+/* { dg-options "-O2 -fmath-errno -fdump-tree-cdce-details -lm
-fno-allocation-dce" } */
/* { dg-additional-options "-DLARGE_LONG_DOUBLE" { target large_long_double }
} */
/* { dg-additional-options "-DGNU_EXTENSION" { target pow10 } } */
/* { dg-add-options ieee } */
diff --git a/gcc/testsuite/g++.dg/tree-ssa/dce-1.C
b/gcc/testsuite/g++.dg/tree-ssa/dce-1.C
new file mode 100644
index 00000000000..1d5115ccb14
--- /dev/null
+++ b/gcc/testsuite/g++.dg/tree-ssa/dce-1.C
@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+#include <new>
+void test ()
+{
+ int *a = new (std::nothrow) int;
+ delete a;
+}
+/* { dg-final { scan-tree-dump-not "operator new" "optimized" } } */
diff --git a/gcc/testsuite/g++.dg/tree-ssa/pr19476-1.C
b/gcc/testsuite/g++.dg/tree-ssa/pr19476-1.C
index 25867185648..d17be88642f 100644
--- a/gcc/testsuite/g++.dg/tree-ssa/pr19476-1.C
+++ b/gcc/testsuite/g++.dg/tree-ssa/pr19476-1.C
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-options "-O -fdump-tree-dom2 -fdelete-null-pointer-checks" } */
+/* { dg-options "-O -fdump-tree-dom2 -fdelete-null-pointer-checks
-fno-allocation-dce" } */
/* { dg-skip-if "" keeps_null_pointer_checks } */
// See pr19476-5.C for a version without including <new>.
diff --git a/gcc/testsuite/g++.dg/tree-ssa/pr19476-2.C
b/gcc/testsuite/g++.dg/tree-ssa/pr19476-2.C
index 0f657d5bd0c..aab7d04ab92 100644
--- a/gcc/testsuite/g++.dg/tree-ssa/pr19476-2.C
+++ b/gcc/testsuite/g++.dg/tree-ssa/pr19476-2.C
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-options "-O2 -fdump-tree-optimized -fdelete-null-pointer-checks" } */
+/* { dg-options "-O2 -fdump-tree-optimized -fdelete-null-pointer-checks
-fno-allocation-dce" } */
/* { dg-skip-if "" keeps_null_pointer_checks } */
#include <new>
diff --git a/gcc/testsuite/g++.dg/tree-ssa/pr19476-3.C
b/gcc/testsuite/g++.dg/tree-ssa/pr19476-3.C
index fd5117fceb8..0894178c470 100644
--- a/gcc/testsuite/g++.dg/tree-ssa/pr19476-3.C
+++ b/gcc/testsuite/g++.dg/tree-ssa/pr19476-3.C
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-options "-O3 -fcheck-new -fdump-tree-optimized" } */
+/* { dg-options "-O3 -fcheck-new -fdump-tree-optimized -fno-allocation-dce" }
*/
#include <new>
diff --git a/gcc/testsuite/g++.dg/tree-ssa/pr19476-4.C
b/gcc/testsuite/g++.dg/tree-ssa/pr19476-4.C
index 5f137391cc6..e5c216a64fa 100644
--- a/gcc/testsuite/g++.dg/tree-ssa/pr19476-4.C
+++ b/gcc/testsuite/g++.dg/tree-ssa/pr19476-4.C
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-options "-O3 -fno-delete-null-pointer-checks -fdump-tree-optimized" }
*/
+/* { dg-options "-O3 -fno-delete-null-pointer-checks -fdump-tree-optimized
-fno-allocation-dce" } */
#include <new>
diff --git a/gcc/testsuite/gcc.dg/analyzer/pr101837.c
b/gcc/testsuite/gcc.dg/analyzer/pr101837.c
index f99374df604..1a1f7f63637 100644
--- a/gcc/testsuite/gcc.dg/analyzer/pr101837.c
+++ b/gcc/testsuite/gcc.dg/analyzer/pr101837.c
@@ -1,4 +1,4 @@
-/* { dg-additional-options "-O3 -fsanitize=undefined" } */
+/* { dg-additional-options "-O3 -fsanitize=undefined -fno-malloc-dce" } */
void memory_exhausted();
void memcheck(void *ptr) {
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr19831-3.c
b/gcc/testsuite/gcc.dg/tree-ssa/pr19831-3.c
index f5cb72daa33..e6ae6582ab2 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/pr19831-3.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr19831-3.c
@@ -29,10 +29,5 @@ void test6(void)
Assume p was non-NULL for test2.
For test5, it doesn't matter if p is NULL or non-NULL. */
-/* { dg-final { scan-tree-dump-times "free" 0 "optimized" { xfail *-*-* } } }
*/
-/* { dg-final { scan-tree-dump-times "malloc" 0 "optimized" { xfail *-*-* } }
} */
-
-/* But make sure we don't partially optimize for now. */
-
-/* { dg-final { scan-tree-dump-times "free" 3 "optimized" } } */
-/* { dg-final { scan-tree-dump-times "malloc" 3 "optimized" } } */
+/* { dg-final { scan-tree-dump-times "free" 0 "optimized" } } */
+/* { dg-final { scan-tree-dump-times "malloc" 0 "optimized" } } */
diff --git a/gcc/testsuite/gfortran.dg/pr68078.f90
b/gcc/testsuite/gfortran.dg/pr68078.f90
index ebe26d55d2b..6494aa62362 100644
--- a/gcc/testsuite/gfortran.dg/pr68078.f90
+++ b/gcc/testsuite/gfortran.dg/pr68078.f90
@@ -1,4 +1,6 @@
! { dg-do run { target i?86-*-linux* x86_64-*-linux* } }
+! disable DCE so the allocations are not optimized away
+! { dg-additional-options "-fno-malloc-dce" }
! { dg-additional-sources set_vm_limit.c }
!
! This test calls set_vm_limit to set an artificially low address space
diff --git a/gcc/tree-ssa-dce.cc b/gcc/tree-ssa-dce.cc
index c44eff35b84..f4807adb926 100644
--- a/gcc/tree-ssa-dce.cc
+++ b/gcc/tree-ssa-dce.cc
@@ -240,6 +240,60 @@ mark_operand_necessary (tree op)
worklist.safe_push (stmt);
}
+/* Return true if STMT is a call to allocation function that can be
+ optimized out if the memory block is never used for anything else
+ then NULL pointer check or free.
+ If NON_NULL_CHECK is false, we can furhter assume that return value
+ is never checked to be non-NULL. */
+
+static bool
+is_removable_allocation_p (gcall *stmt, bool non_null_check)
+{
+ tree callee = gimple_call_fndecl (stmt);
+ if (callee != NULL_TREE
+ && fndecl_built_in_p (callee, BUILT_IN_NORMAL))
+ switch (DECL_FUNCTION_CODE (callee))
+ {
+ case BUILT_IN_MALLOC:
+ case BUILT_IN_ALIGNED_ALLOC:
+ case BUILT_IN_CALLOC:
+ CASE_BUILT_IN_ALLOCA:
+ case BUILT_IN_STRDUP:
+ case BUILT_IN_STRNDUP:
+ return non_null_check ? flag_malloc_dce > 1 : flag_malloc_dce;
+
+ case BUILT_IN_GOMP_ALLOC:
+ return true;
+
+ default:;
+ }
+
+ if (callee != NULL_TREE
+ && flag_allocation_dce
+ && gimple_call_from_new_or_delete (stmt)
+ && DECL_IS_REPLACEABLE_OPERATOR_NEW_P (callee))
+ return true;
+ return false;
+}
+
+/* Return true if STMT is a conditional
+ if (ptr != NULL)
+ where ptr was returned by a removable allocation function. */
+
+static bool
+checks_return_value_of_removable_allocation_p (gimple *stmt)
+{
+ gcall *def_stmt;
+ return gimple_code (stmt) == GIMPLE_COND
+ && (gimple_cond_code (stmt) == EQ_EXPR
+ || gimple_cond_code (stmt) == NE_EXPR)
+ && integer_zerop (gimple_cond_rhs (stmt))
+ && TREE_CODE (gimple_cond_lhs (stmt)) == SSA_NAME
+ && (def_stmt = dyn_cast <gcall *>
+ (SSA_NAME_DEF_STMT (gimple_cond_lhs (stmt))))
+ && is_removable_allocation_p (def_stmt, true);
+}
+
/* Mark STMT as necessary if it obviously is. Add it to the worklist if
it can make other statements necessary.
@@ -271,38 +325,23 @@ mark_stmt_if_obviously_necessary (gimple *stmt, bool
aggressive)
case GIMPLE_CALL:
{
+ gcall *call = as_a <gcall *> (stmt);
+
/* Never elide a noreturn call we pruned control-flow for. */
- if ((gimple_call_flags (stmt) & ECF_NORETURN)
- && gimple_call_ctrl_altering_p (stmt))
+ if ((gimple_call_flags (call) & ECF_NORETURN)
+ && gimple_call_ctrl_altering_p (call))
{
- mark_stmt_necessary (stmt, true);
+ mark_stmt_necessary (call, true);
return;
}
- tree callee = gimple_call_fndecl (stmt);
- if (callee != NULL_TREE
- && fndecl_built_in_p (callee, BUILT_IN_NORMAL))
- switch (DECL_FUNCTION_CODE (callee))
- {
- case BUILT_IN_MALLOC:
- case BUILT_IN_ALIGNED_ALLOC:
- case BUILT_IN_CALLOC:
- CASE_BUILT_IN_ALLOCA:
- case BUILT_IN_STRDUP:
- case BUILT_IN_STRNDUP:
- case BUILT_IN_GOMP_ALLOC:
- return;
-
- default:;
- }
- if (callee != NULL_TREE
- && flag_allocation_dce
- && DECL_IS_REPLACEABLE_OPERATOR_NEW_P (callee))
+ if (is_removable_allocation_p (call, false))
return;
+
/* For __cxa_atexit calls, don't mark as necessary right away. */
- if (is_removable_cxa_atexit_call (stmt))
+ if (is_removable_cxa_atexit_call (call))
return;
/* IFN_GOACC_LOOP calls are necessary in that they are used to
@@ -311,9 +350,9 @@ mark_stmt_if_obviously_necessary (gimple *stmt, bool
aggressive)
survive from aggressive loop removal for it has loop exit and
is assumed to be finite. Therefore, we need to explicitly mark
these calls. (An example is libgomp.oacc-c-c++-common/pr84955.c) */
- if (gimple_call_internal_p (stmt, IFN_GOACC_LOOP))
+ if (gimple_call_internal_p (call, IFN_GOACC_LOOP))
{
- mark_stmt_necessary (stmt, true);
+ mark_stmt_necessary (call, true);
return;
}
break;
@@ -667,6 +706,8 @@ mark_all_reaching_defs_necessary_1 (ao_ref *ref
ATTRIBUTE_UNUSED,
case BUILT_IN_ALIGNED_ALLOC:
case BUILT_IN_CALLOC:
CASE_BUILT_IN_ALLOCA:
+ case BUILT_IN_STRDUP:
+ case BUILT_IN_STRNDUP:
case BUILT_IN_FREE:
case BUILT_IN_GOMP_ALLOC:
case BUILT_IN_GOMP_FREE:
@@ -891,19 +932,11 @@ propagate_necessity (bool aggressive)
{
tree ptr = gimple_call_arg (stmt, 0);
gcall *def_stmt;
- tree def_callee;
/* If the pointer we free is defined by an allocation
function do not add the call to the worklist. */
if (TREE_CODE (ptr) == SSA_NAME
&& (def_stmt = dyn_cast <gcall *> (SSA_NAME_DEF_STMT (ptr)))
- && (def_callee = gimple_call_fndecl (def_stmt))
- && ((DECL_BUILT_IN_CLASS (def_callee) == BUILT_IN_NORMAL
- && (DECL_FUNCTION_CODE (def_callee) ==
BUILT_IN_ALIGNED_ALLOC
- || DECL_FUNCTION_CODE (def_callee) == BUILT_IN_MALLOC
- || DECL_FUNCTION_CODE (def_callee) == BUILT_IN_CALLOC
- || DECL_FUNCTION_CODE (def_callee) ==
BUILT_IN_GOMP_ALLOC))
- || (DECL_IS_REPLACEABLE_OPERATOR_NEW_P (def_callee)
- && gimple_call_from_new_or_delete (def_stmt))))
+ && is_removable_allocation_p (def_stmt, false))
{
if (is_delete_operator
&& !valid_new_delete_pair_p (def_stmt, stmt))
@@ -925,6 +958,9 @@ propagate_necessity (bool aggressive)
}
}
+ if (checks_return_value_of_removable_allocation_p (stmt))
+ continue;
+
FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE)
mark_operand_necessary (use);
@@ -1379,7 +1415,6 @@ eliminate_unnecessary_stmts (bool aggressive)
basic_block bb;
gimple_stmt_iterator gsi, psi;
gimple *stmt;
- tree call;
auto_vec<edge> to_remove_edges;
if (dump_file && (dump_flags & TDF_DETAILS))
@@ -1448,6 +1483,23 @@ eliminate_unnecessary_stmts (bool aggressive)
gimple_set_plf (stmt, STMT_NECESSARY, false);
}
}
+ /* Conditional checking that return value of allocation is non-NULL
+ can be turned to constant if the allocation itself
+ is unnecesary. */
+ if (gimple_plf (stmt, STMT_NECESSARY)
+ && gimple_code (stmt) == GIMPLE_COND
+ && TREE_CODE (gimple_cond_lhs (stmt)) == SSA_NAME)
+ {
+ gimple *def_stmt = SSA_NAME_DEF_STMT (gimple_cond_lhs (stmt));
+ if (!gimple_nop_p (def_stmt)
+ && !gimple_plf (def_stmt, STMT_NECESSARY))
+ {
+ gcc_checking_assert
+ (checks_return_value_of_removable_allocation_p (stmt));
+ gimple_cond_set_lhs (as_a <gcond *>(stmt), integer_one_node);
+ update_stmt (stmt);
+ }
+ }
/* If GSI is not necessary then remove it. */
if (!gimple_plf (stmt, STMT_NECESSARY))
@@ -1482,11 +1534,11 @@ eliminate_unnecessary_stmts (bool aggressive)
remove_dead_stmt (&gsi, bb, to_remove_edges);
continue;
}
- else if (is_gimple_call (stmt))
+ else if (gcall *call_stmt = dyn_cast <gcall *> (stmt))
{
- tree name = gimple_call_lhs (stmt);
+ tree name = gimple_call_lhs (call_stmt);
- notice_special_calls (as_a <gcall *> (stmt));
+ notice_special_calls (call_stmt);
/* When LHS of var = call (); is dead, simplify it into
call (); saving one operand. */
@@ -1496,36 +1548,30 @@ eliminate_unnecessary_stmts (bool aggressive)
/* Avoid doing so for allocation calls which we
did not mark as necessary, it will confuse the
special logic we apply to malloc/free pair removal. */
- && (!(call = gimple_call_fndecl (stmt))
- || ((DECL_BUILT_IN_CLASS (call) != BUILT_IN_NORMAL
- || (DECL_FUNCTION_CODE (call) !=
BUILT_IN_ALIGNED_ALLOC
- && DECL_FUNCTION_CODE (call) != BUILT_IN_MALLOC
- && DECL_FUNCTION_CODE (call) != BUILT_IN_CALLOC
- && !ALLOCA_FUNCTION_CODE_P
- (DECL_FUNCTION_CODE (call))))
- && !DECL_IS_REPLACEABLE_OPERATOR_NEW_P (call))))
+ && !is_removable_allocation_p (call_stmt, false))
{
something_changed = true;
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Deleting LHS of call: ");
- print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
+ print_gimple_stmt (dump_file, call_stmt, 0, TDF_SLIM);
fprintf (dump_file, "\n");
}
- gimple_call_set_lhs (stmt, NULL_TREE);
- maybe_clean_or_replace_eh_stmt (stmt, stmt);
- update_stmt (stmt);
+ gimple_call_set_lhs (call_stmt, NULL_TREE);
+ maybe_clean_or_replace_eh_stmt (call_stmt, call_stmt);
+ update_stmt (call_stmt);
release_ssa_name (name);
/* GOMP_SIMD_LANE (unless three argument) or ASAN_POISON
without lhs is not needed. */
- if (gimple_call_internal_p (stmt))
- switch (gimple_call_internal_fn (stmt))
+ if (gimple_call_internal_p (call_stmt))
+ switch (gimple_call_internal_fn (call_stmt))
{
case IFN_GOMP_SIMD_LANE:
- if (gimple_call_num_args (stmt) >= 3
- && !integer_nonzerop (gimple_call_arg (stmt, 2)))
+ if (gimple_call_num_args (call_stmt) >= 3
+ && !integer_nonzerop
+ (gimple_call_arg (call_stmt, 2)))
break;
/* FALLTHRU */
case IFN_ASAN_POISON:
@@ -1535,8 +1581,8 @@ eliminate_unnecessary_stmts (bool aggressive)
break;
}
}
- else if (gimple_call_internal_p (stmt))
- switch (gimple_call_internal_fn (stmt))
+ else if (gimple_call_internal_p (call_stmt))
+ switch (gimple_call_internal_fn (call_stmt))
{
case IFN_ADD_OVERFLOW:
maybe_optimize_arith_overflow (&gsi, PLUS_EXPR);
@@ -1548,11 +1594,11 @@ eliminate_unnecessary_stmts (bool aggressive)
maybe_optimize_arith_overflow (&gsi, MULT_EXPR);
break;
case IFN_UADDC:
- if (integer_zerop (gimple_call_arg (stmt, 2)))
+ if (integer_zerop (gimple_call_arg (call_stmt, 2)))
maybe_optimize_arith_overflow (&gsi, PLUS_EXPR);
break;
case IFN_USUBC:
- if (integer_zerop (gimple_call_arg (stmt, 2)))
+ if (integer_zerop (gimple_call_arg (call_stmt, 2)))
maybe_optimize_arith_overflow (&gsi, MINUS_EXPR);
break;
default:
