Hi DJ,
Compiling this test case with the RL78 toolchain results in an ICE:
unsigned char g_X;
unsigned char g_Y;
const __far unsigned char TabA[2][2] = { { 3, 0 }, { 4, 5 } };
void main (void) { g_X = 1; g_Y = TabA[g_X][g_X]; }
The problem appears to be that GCC will create a multiply-plus-add
instruction to access the table regardless of whether the backend
supports such an instruction. I could not work out where in the
middle end this was occurring, so instead I created the patch below
which contains a splitter to separate out the multiply and addition
operations.
Tested with no regressions on an rl78-elf toolchain.
OK to apply ?
Cheers
Nick
gcc/ChangeLog
2015-03-03 Nick Clifton <[email protected]>
* config/rl78/rl78.md (muladdhi4): New splitter.
Index: gcc/config/rl78/rl78.md
===================================================================
--- gcc/config/rl78/rl78.md (revision 221150)
+++ gcc/config/rl78/rl78.md (working copy)
@@ -441,3 +441,15 @@
""
""
)
+
+(define_insn_and_split "muladdhi4"
+ [(set (match_operand:HI 0 "register_operand" "=&v")
+ (plus:HI (mult:HI (match_operand:HI 1 "general_operand" "vi")
+ (match_operand:HI 2 "general_operand" "vi"))
+ (match_operand:HI 3 "register_operand" "v")))]
+ "! RL78_MUL_NONE"
+ "#"
+ ""
+ [(set (match_dup 0) (mult:HI (match_dup 1) (match_dup 2)))
+ (set (match_dup 0) (plus:HI (match_dup 0) (match_dup 3)))]
+)
