From: Richard Biener <rguenther@suse.de>
Date: Thu, 31 Mar 2022 07:21:27 +0000 (+0200)
Subject: tree-optimization/105109 - bogus uninit diagnostic with _Complex
X-Git-Tag: basepoints/gcc-13~379
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=97ad0b831386e56ecb125a25fff00b2cb0b1a2b9;p=thirdparty%2Fgcc.git

tree-optimization/105109 - bogus uninit diagnostic with _Complex

When update_address_taken rewrites a _Complex into SSA it changes
stores to real/imaginary parts to loads of the other component and
a COMPLEX_EXPR.  That matches what gimplification does but it misses
suppression of diagnostics for the load of the other component.
The following patch adds that, syncing up gimplification and
update_address_taken behavior.

2022-03-31  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/105109
	* tree-ssa.cc (execute_update_addresses_taken): Suppress
	diagnostics on the load of the other complex component.

	* gcc.dg/uninit-pr105109.c: New testcase.
---

diff --git a/gcc/testsuite/gcc.dg/uninit-pr105109.c b/gcc/testsuite/gcc.dg/uninit-pr105109.c
new file mode 100644
index 000000000000..001003ca2613
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/uninit-pr105109.c
@@ -0,0 +1,15 @@
+/* { dg-do compile } */
+/* { dg-options "-O -Wuninitialized" } */
+
+static void foo(int dim,float _Complex f0[])
+{
+  int d;
+  f0[0] -= 3.14;  /* { dg-bogus "uninitialized" } */
+  for (d = 0; d < dim; ++d) f0[0] += 3.14;
+}
+void bar(int dim, const float _Complex u_t[], float _Complex f0[])
+{
+  float _Complex exp[1] = {0.};
+  foo(dim, exp);
+  f0[0] = u_t[0] - exp[0];
+}
diff --git a/gcc/tree-ssa.cc b/gcc/tree-ssa.cc
index 6dcb31428699..a362a0a9ea63 100644
--- a/gcc/tree-ssa.cc
+++ b/gcc/tree-ssa.cc
@@ -1905,6 +1905,7 @@ execute_update_addresses_taken (void)
 					? REALPART_EXPR : IMAGPART_EXPR,
 					TREE_TYPE (other),
 					TREE_OPERAND (lhs, 0));
+		    suppress_warning (lrhs);
 		    gimple *load = gimple_build_assign (other, lrhs);
 		    location_t loc = gimple_location (stmt);
 		    gimple_set_location (load, loc);