[PATCH] LoongArch: Support Q suffix for __float128.

[Lulu Cheng]

In r14-3635 supports `__float128`, but does not support the 'q/Q' suffix.

        PR target/119408

gcc/ChangeLog:

        * config/loongarch/loongarch.cc
        (loongarch_c_mode_for_suffix): New.
        (TARGET_C_MODE_FOR_SUFFIX): Define.

gcc/testsuite/ChangeLog:

        * gcc.target/loongarch/pr119408.c: New test.

---
 gcc/config/loongarch/loongarch.cc             | 13 +++++++++++++
 gcc/testsuite/gcc.target/loongarch/pr119408.c | 12 ++++++++++++
 2 files changed, 25 insertions(+)
 create mode 100644 gcc/testsuite/gcc.target/loongarch/pr119408.c

diff --git a/gcc/config/loongarch/loongarch.cc 
b/gcc/config/loongarch/loongarch.cc
index 01f048664b5..7533e53839f 100644
--- a/gcc/config/loongarch/loongarch.cc
+++ b/gcc/config/loongarch/loongarch.cc
@@ -11206,6 +11206,16 @@ loongarch_asm_code_end (void)
 #undef DUMP_FEATURE
 }
 
+/* Target hook for c_mode_for_suffix.  */
+static machine_mode
+loongarch_c_mode_for_suffix (char suffix)
+{
+  if (suffix == 'q')
+    return TFmode;
+
+  return VOIDmode;
+}
+
 /* Initialize the GCC target structure.  */
 #undef TARGET_ASM_ALIGNED_HI_OP
 #define TARGET_ASM_ALIGNED_HI_OP "\t.half\t"
@@ -11477,6 +11487,9 @@ loongarch_asm_code_end (void)
 #undef TARGET_OPTION_VALID_ATTRIBUTE_P
 #define TARGET_OPTION_VALID_ATTRIBUTE_P loongarch_option_valid_attribute_p
 
+#undef TARGET_C_MODE_FOR_SUFFIX
+#define TARGET_C_MODE_FOR_SUFFIX loongarch_c_mode_for_suffix
+
 struct gcc_target targetm = TARGET_INITIALIZER;
 
 #include "gt-loongarch.h"
diff --git a/gcc/testsuite/gcc.target/loongarch/pr119408.c 
b/gcc/testsuite/gcc.target/loongarch/pr119408.c
new file mode 100644
index 00000000000..f46399aa0b5
--- /dev/null
+++ b/gcc/testsuite/gcc.target/loongarch/pr119408.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -Wno-pedantic" } */
+
+__float128 a;
+__float128 b;
+void
+test (void)
+{
+  a = 1.11111111Q;
+  b = 1.434345q;       
+}
+
-- 
2.34.1