varasm: Handle RAW_DATA_CST in compare_constant [PR117199]

On the following testcase without LTO we unnecessarily don't merge
two identical .LC* constants (constant hashing computes the same hash,
but as compare_constant returned false for the RAW_DATA_CST in it,
it never compares equal), and with LTO fails to link because LTO assumes such
constants have to be merged and so doesn't emit the other constant.

2024-10-22  Jakub Jelinek  <jakub@redhat.com>

	PR middle-end/117199
	* varasm.cc (compare_constant): Handle RAW_DATA_CST.  Formatting fix
	in the STRING_CST case.

	* gcc.dg/lto/pr117199_0.c: New test.

diff --git a/gcc/testsuite/gcc.dg/lto/pr117199_0.c b/gcc/testsuite/gcc.dg/lto/pr117199_0.c
new file mode 100644 (file)
index 0000000..d47b491
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/lto/pr117199_0.c
@@ -0,0 +1,45 @@
+/* PR middle-end/117199 */
+/* { dg-lto-do link } */
+/* { dg-lto-options { "-O2 -flto" } } */
+/* { dg-lto-options { "-O2 -flto -mtune=znver3" } { target i?86-*-* x86_64-*-* } } */
+
+__attribute__((used)) void
+foo (int *x, int y, int z)
+{
+  const unsigned char v[128] = {
+    0, 64, 32, 96, 16, 80, 48, 112,
+    8, 72, 40, 104, 24, 88, 56, 120,
+    4, 68, 36, 100, 20, 84, 52, 116,
+    12, 76, 44, 108, 28, 92, 60, 124,
+    2, 66, 34, 98, 18, 82, 50, 114,
+    10, 74, 42, 106, 26, 90, 58, 122,
+    6, 70, 38, 102, 22, 86, 54, 118,
+    14, 78, 46, 110, 30, 94, 62, 126,
+    1, 65, 33, 97, 17, 81, 49, 113,
+    9, 73, 41, 105, 25, 89, 57, 121
+  };
+  x[v[z]] = 1;
+}
+
+__attribute__((used)) void
+bar (int *x, int y, int z)
+{
+  const unsigned char v[128] = {
+    0, 64, 32, 96, 16, 80, 48, 112,
+    8, 72, 40, 104, 24, 88, 56, 120,
+    4, 68, 36, 100, 20, 84, 52, 116,
+    12, 76, 44, 108, 28, 92, 60, 124,
+    2, 66, 34, 98, 18, 82, 50, 114,
+    10, 74, 42, 106, 26, 90, 58, 122,
+    6, 70, 38, 102, 22, 86, 54, 118,
+    14, 78, 46, 110, 30, 94, 62, 126,
+    1, 65, 33, 97, 17, 81, 49, 113,
+    9, 73, 41, 105, 25, 89, 57, 121
+  };
+  x[v[z]] = 2;
+}
+
+int
+main ()
+{
+}

diff --git a/gcc/varasm.cc b/gcc/varasm.cc
index 0b3e8005cd313e02cec20b877962250c77cf3bb9..8e492e37fb08715f05711f6ccb9140fffe4ee5b0 100644 (file)
--- a/gcc/varasm.cc
+++ b/gcc/varasm.cc
@@ -3331,7 +3331,7 @@ compare_constant (const tree t1, const tree t2)
 
       return (TREE_STRING_LENGTH (t1) == TREE_STRING_LENGTH (t2)
              && ! memcmp (TREE_STRING_POINTER (t1), TREE_STRING_POINTER (t2),
-                        TREE_STRING_LENGTH (t1)));
+                          TREE_STRING_LENGTH (t1)));
 
     case COMPLEX_CST:
       return (compare_constant (TREE_REALPART (t1), TREE_REALPART (t2))
@@ -3356,6 +3356,11 @@ compare_constant (const tree t1, const tree t2)
        return true;
       }
 
+    case RAW_DATA_CST:
+      return (RAW_DATA_LENGTH (t1) == RAW_DATA_LENGTH (t2)
+             && ! memcmp (RAW_DATA_POINTER (t1), RAW_DATA_POINTER (t2),
+                          RAW_DATA_LENGTH (t1)));
+
     case CONSTRUCTOR:
       {
        vec<constructor_elt, va_gc> *v1, *v2;