From: Marek Polacek <polacek@redhat.com>
Date: Tue, 29 Mar 2022 18:36:55 +0000 (-0400)
Subject: c-family: ICE with -Wconversion and A ?: B [PR101030]
X-Git-Tag: releases/gcc-11.3.0~142
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=511e8b612287ad828c60f2f12c500ccfa26c275c;p=thirdparty%2Fgcc.git

c-family: ICE with -Wconversion and A ?: B [PR101030]

This patch fixes a crash in conversion_warning on a null expression.
It is null because the testcase uses the GNU A ?: B extension.  We
could also use op0 instead of op1 in this case, but it doesn't seem
to be necessary.

	PR c++/101030

gcc/c-family/ChangeLog:

	* c-warn.c (conversion_warning) <case COND_EXPR>: Don't call
	conversion_warning when OP1 is null.

gcc/testsuite/ChangeLog:

	* g++.dg/ext/cond5.C: New test.

(cherry picked from commit 5db9ce171019f8915885cebd5cc5f4101bb926e6)
---

diff --git a/gcc/c-family/c-warn.c b/gcc/c-family/c-warn.c
index abd6adcfe9a9..96bee7d19845 100644
--- a/gcc/c-family/c-warn.c
+++ b/gcc/c-family/c-warn.c
@@ -1300,7 +1300,7 @@ conversion_warning (location_t loc, tree type, tree expr, tree result)
 	tree op1 = TREE_OPERAND (expr, 1);
 	tree op2 = TREE_OPERAND (expr, 2);
 
-	return (conversion_warning (loc, type, op1, result)
+	return ((op1 && conversion_warning (loc, type, op1, result))
 		|| conversion_warning (loc, type, op2, result));
       }
 
diff --git a/gcc/testsuite/g++.dg/ext/cond5.C b/gcc/testsuite/g++.dg/ext/cond5.C
new file mode 100644
index 000000000000..a92f28998f93
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/cond5.C
@@ -0,0 +1,13 @@
+// PR c++/101030
+// { dg-do compile { target { c++11 } } }
+// { dg-options "-Wconversion" }
+
+template <int N>
+struct jj {
+    int ii[N ?: 1];
+    char c = N ?: 1; // { dg-warning "conversion from .int. to .char. changes value from .300. to " }
+};
+
+int main() {
+    jj<300> kk;
+}