| Message ID | 000c01d66834$01eaee10$05c0ca30$@nextmovesoftware.com |
|---|---|
| State | New |
| Headers | show |
| Series | genmatch: Avoid unused parameter warnings in generated code. | expand |
On Sat, Aug 1, 2020 at 8:46 PM Roger Sayle <roger@nextmovesoftware.com> wrote: > > > This patch silences a number of unused parameter warnings whilst > compiling both generic-match.c and gimple-match.c. The problem is > that multiple (polymorphic) functions are generated for generic_simplify > and gimple_simplify, each handling tree codes with a specific number > of children. Currently, there are no simplifications for tree codes > with four or five children, leading to functions with "empty" bodies > and unused function arguments. This patch detects those cases, and > generates stub functions (with anonymous arguments) to silence these > warnings. > > Previously, genmatch would generate: > > static bool > gimple_simplify (gimple_match_op *res_op, gimple_seq *seq, > tree (*valueize)(tree) ATTRIBUTE_UNUSED, > code_helper code, const tree type, tree _p0, tree _p1, tree > _p2, tree _p3) > { > switch (code.get_rep()) > { > default:; > } > return false; > } > > which results in: > gimple_simplify (gimple_match_op *res_op, gimple_seq *seq, > ^ > gimple-match.c:130408:1: warning: unused parameter 'seq' > [-Wunused-parameter] > gimple-match.c:130408:1: warning: unused parameter 'type' > [-Wunused-parameter] > gimple-match.c:130408:1: warning: unused parameter '_p0' > [-Wunused-parameter] > gimple-match.c:130408:1: warning: unused parameter '_p1' > [-Wunused-parameter] > gimple-match.c:130408:1: warning: unused parameter '_p2' > [-Wunused-parameter] > gimple-match.c:130408:1: warning: unused parameter '_p3' > [-Wunused-parameter] > gimple-match.c:130420:1: warning: unused parameter 'res_op' > [-Wunused-parameter] > > With this patch genmatch now generates: > static bool > gimple_simplify (gimple_match_op*, gimple_seq*, > tree (*)(tree), code_helper, > const tree, tree, tree, tree, tree) > { > return false; > } > > which has the same signature but no compilation warnings. > > This patch has been tested on x86_64-pc-linux-gnu with a full > "make bootstrap" and "make -k check" with no new failures. > Ok for mainline? OK. Thanks, Richard. > > 2020-08-01 Roger Sayle <roger@nextmovesoftware.com> > > * gcc/genmatch.c (decision_tree::gen): Emit stub functions for > tree code operand counts that have no simplifications. > (main): Correct comment typo. > > Thanks in advance, > Roger > -- > Roger Sayle > NextMove Software > Cambridge, UK >
diff --git a/gcc/genmatch.c b/gcc/genmatch.c index 0a8cba6..022ad8d 100644 --- a/gcc/genmatch.c +++ b/gcc/genmatch.c @@ -3798,6 +3798,8 @@ decision_tree::gen (FILE *f, bool gimple) for (unsigned n = 1; n <= 5; ++n) { + bool has_kids_p = false; + /* First generate split-out functions. */ for (unsigned j = 0; j < root->kids.length (); j++) { @@ -3836,6 +3838,32 @@ decision_tree::gen (FILE *f, bool gimple) else fprintf (f, " return NULL_TREE;\n"); fprintf (f, "}\n"); + has_kids_p = true; + } + + /* If this main entry has no children, avoid generating code + with compiler warnings, by generating a simple stub. */ + if (! has_kids_p) + { + if (gimple) + fprintf (f, "\nstatic bool\n" + "gimple_simplify (gimple_match_op*, gimple_seq*,\n" + " tree (*)(tree), code_helper,\n" + " const tree"); + else + fprintf (f, "\ntree\n" + "generic_simplify (location_t, enum tree_code,\n" + " const tree"); + for (unsigned i = 0; i < n; ++i) + fprintf (f, ", tree"); + fprintf (f, ")\n"); + fprintf (f, "{\n"); + if (gimple) + fprintf (f, " return false;\n"); + else + fprintf (f, " return NULL_TREE;\n"); + fprintf (f, "}\n"); + continue; } /* Then generate the main entry with the outermost switch and @@ -5061,7 +5089,7 @@ round_alloc_size (size_t s) } -/* The genmatch generator progam. It reads from a pattern description +/* The genmatch generator program. It reads from a pattern description and outputs GIMPLE or GENERIC IL matching and simplification routines. */ int
This patch silences a number of unused parameter warnings whilst compiling both generic-match.c and gimple-match.c. The problem is that multiple (polymorphic) functions are generated for generic_simplify and gimple_simplify, each handling tree codes with a specific number of children. Currently, there are no simplifications for tree codes with four or five children, leading to functions with "empty" bodies and unused function arguments. This patch detects those cases, and generates stub functions (with anonymous arguments) to silence these warnings. Previously, genmatch would generate: static bool gimple_simplify (gimple_match_op *res_op, gimple_seq *seq, tree (*valueize)(tree) ATTRIBUTE_UNUSED, code_helper code, const tree type, tree _p0, tree _p1, tree _p2, tree _p3) { switch (code.get_rep()) { default:; } return false; } which results in: gimple_simplify (gimple_match_op *res_op, gimple_seq *seq, ^ gimple-match.c:130408:1: warning: unused parameter 'seq' [-Wunused-parameter] gimple-match.c:130408:1: warning: unused parameter 'type' [-Wunused-parameter] gimple-match.c:130408:1: warning: unused parameter '_p0' [-Wunused-parameter] gimple-match.c:130408:1: warning: unused parameter '_p1' [-Wunused-parameter] gimple-match.c:130408:1: warning: unused parameter '_p2' [-Wunused-parameter] gimple-match.c:130408:1: warning: unused parameter '_p3' [-Wunused-parameter] gimple-match.c:130420:1: warning: unused parameter 'res_op' [-Wunused-parameter] With this patch genmatch now generates: static bool gimple_simplify (gimple_match_op*, gimple_seq*, tree (*)(tree), code_helper, const tree, tree, tree, tree, tree) { return false; } which has the same signature but no compilation warnings. This patch has been tested on x86_64-pc-linux-gnu with a full "make bootstrap" and "make -k check" with no new failures. Ok for mainline? 2020-08-01 Roger Sayle <roger@nextmovesoftware.com> * gcc/genmatch.c (decision_tree::gen): Emit stub functions for tree code operand counts that have no simplifications. (main): Correct comment typo. Thanks in advance, Roger -- Roger Sayle NextMove Software Cambridge, UK