MIPS: Workaround clang inline compat branch issue

Clang is unable to handle the situation that a chunk of inline
assembly ends with a compat branch instruction and then compiler
generates another control transfer instruction immediately after
this compat branch. The later instruction will end up in forbidden
slot and cause exception.

Workaround by add a option to control the use of compact branch.
Currently it's selected by CC_IS_CLANG and hopefully we can change
it to a version check in future if clang manages to fix it.

Fix boot on boston board.

Link: llvm/llvm-project#61045
Signed-off-by: Jiaxun Yang <[email protected]>
Acked-by: Nathan Chancellor <[email protected]>
Acked-by: Nick Desaulniers <[email protected]>
Signed-off-by: Thomas Bogendoerfer <[email protected]>

Author: FlyGoat

arch/mips/Kconfig

@@ -3200,6 +3200,10 @@ config CC_HAS_MNO_BRANCH_LIKELY
 	def_bool y
 	depends on $(cc-option,-mno-branch-likely)
 
+# https://github.com/llvm/llvm-project/issues/61045
+config CC_HAS_BROKEN_INLINE_COMPAT_BRANCH
+	def_bool y if CC_IS_CLANG
+
 menu "Power management options"
 
 config ARCH_HIBERNATION_POSSIBLE

arch/mips/include/asm/asm.h

@@ -336,7 +336,7 @@ symbol		=	value
  */
 #ifdef CONFIG_WAR_R10000_LLSC
 # define SC_BEQZ	beqzl
-#elif MIPS_ISA_REV >= 6
+#elif !defined(CONFIG_CC_HAS_BROKEN_INLINE_COMPAT_BRANCH) && MIPS_ISA_REV >= 6
 # define SC_BEQZ	beqzc
 #else
 # define SC_BEQZ	beqz