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From a252bbd11d22481a1e719ed36d800e2192abb369 Mon Sep 17 00:00:00 2001
From: Pronin Alexander <pronin.alexander@huawei.com>
Date: Thu, 31 Oct 2024 15:49:27 +0800
Subject: [PATCH 1/6] Mark prefetch builtin as willreturn
Signed-off-by: Pronin Alexander <pronin.alexander@huawei.com>
---
gcc/common.opt | 4 ++++
gcc/gimple.cc | 30 ++++++++++++++++++++++++++++++
gcc/gimple.h | 1 +
gcc/tree-ssa-pre.cc | 4 +---
4 files changed, 36 insertions(+), 3 deletions(-)
diff --git a/gcc/common.opt b/gcc/common.opt
index 688d65e4d..be5fcc681 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -1313,6 +1313,10 @@ fdelete-null-pointer-checks
Common Var(flag_delete_null_pointer_checks) Init(-1) Optimization
Delete useless null pointer checks.
+fbuiltin-will-return
+Common Var(flag_builtin_will_return) Optimization
+Consider some of the builtins as definitely returning.
+
fdevirtualize-at-ltrans
Common Var(flag_ltrans_devirtualize)
Stream extra data to support more aggressive devirtualization in LTO local transformation mode.
diff --git a/gcc/gimple.cc b/gcc/gimple.cc
index 9e62da426..04ca9f161 100644
--- a/gcc/gimple.cc
+++ b/gcc/gimple.cc
@@ -2998,6 +2998,36 @@ nonbarrier_call_p (gimple *call)
return false;
}
+static inline bool
+will_return_builtin_p (gimple *call)
+{
+ if (!flag_builtin_will_return)
+ return false;
+
+ if (!gimple_call_builtin_p (call, BUILT_IN_NORMAL))
+ return false;
+
+ switch (DECL_FUNCTION_CODE (gimple_call_fndecl (call)))
+ {
+ case BUILT_IN_PREFETCH:
+ return true;
+ default:
+ return false;
+ }
+}
+
+bool
+will_return_call_p (gimple *call, function *fun)
+{
+ int flags = gimple_call_flags (call);
+ if (!(flags & (ECF_CONST|ECF_PURE))
+ || (flags & ECF_LOOPING_CONST_OR_PURE)
+ || stmt_can_throw_external (fun, call))
+ return will_return_builtin_p (call);
+
+ return true;
+}
+
/* Callback for walk_stmt_load_store_ops.
Return TRUE if OP will dereference the tree stored in DATA, FALSE
diff --git a/gcc/gimple.h b/gcc/gimple.h
index 77a5a07e9..bb05a7664 100644
--- a/gcc/gimple.h
+++ b/gcc/gimple.h
@@ -1628,6 +1628,7 @@ extern bool gimple_asm_clobbers_memory_p (const gasm *);
extern void dump_decl_set (FILE *, bitmap);
extern bool nonfreeing_call_p (gimple *);
extern bool nonbarrier_call_p (gimple *);
+extern bool will_return_call_p (gimple *, function *);
extern bool infer_nonnull_range (gimple *, tree);
extern bool infer_nonnull_range_by_dereference (gimple *, tree);
extern bool infer_nonnull_range_by_attribute (gimple *, tree);
diff --git a/gcc/tree-ssa-pre.cc b/gcc/tree-ssa-pre.cc
index 98134b5d3..b5264133a 100644
--- a/gcc/tree-ssa-pre.cc
+++ b/gcc/tree-ssa-pre.cc
@@ -3988,9 +3988,7 @@ compute_avail (function *fun)
that forbids hoisting possibly trapping expressions
before it. */
int flags = gimple_call_flags (stmt);
- if (!(flags & (ECF_CONST|ECF_PURE))
- || (flags & ECF_LOOPING_CONST_OR_PURE)
- || stmt_can_throw_external (fun, stmt))
+ if (!will_return_call_p (stmt, fun))
/* Defer setting of BB_MAY_NOTRETURN to avoid it
influencing the processing of the call itself. */
set_bb_may_notreturn = true;
--
2.33.0
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