[PR tree-optimization/117895] Fix sparc libgo build failure with CRC opts enabled

So as noted in the BZ, sparc builds of the golang libraries were failing due to
the CRC code.

Ultimately this was another mode problem in the table expansion.  Essentially
when the mode of the resultant crc was different than the mode of the input
data we could create mixed mode operations which is a no-no.  Not entirely sure
how we were getting away with it before, but it was clearly wrong.

The mode of the crc will always be at least as large at the mode of the data
for the cases we support.  So the code has been adjusted to convert the data's
mode to the crc's mode and do all the ops in the crc mode.

That fixes the libgo build problem on sparc and I've verfied that there aren't
any regressions on x86_64 as well as all the embedded targets in my tester.

	PR tree-optimization/117895
gcc/
	* expr.cc (calculate_table_based_CRC): Drop CRC_MODE argument.
	Convert DATA to CRC's mode, then do calculations in CRC's mode.
	(expand_crc_table_based): Corresponding changes.
	(expand_reversed_crc_table_based): Corresponding changes.

1 files changed, 14 insertions, 11 deletions

diff --git a/gcc/expr.cc b/gcc/expr.cc
index 5578e3d..980ac41 100644
--- a/gcc/expr.cc
+++ b/gcc/expr.cc
@@ -14336,29 +14336,32 @@ generate_crc_table (unsigned HOST_WIDE_INT polynom, unsigned short crc_bits)
 void
 calculate_table_based_CRC (rtx *crc, const rtx &input_data,
 			   const rtx &polynomial,
-			   machine_mode crc_mode, machine_mode data_mode)
+			   machine_mode data_mode)
 {
-  unsigned short crc_bit_size = GET_MODE_BITSIZE (crc_mode).to_constant ();
-  unsigned short data_size = GET_MODE_SIZE (data_mode).to_constant ();
   machine_mode mode = GET_MODE (*crc);
+  unsigned short crc_bit_size = GET_MODE_BITSIZE (mode).to_constant ();
+  unsigned short data_size = GET_MODE_SIZE (data_mode).to_constant ();
   rtx tab = generate_crc_table (UINTVAL (polynomial), crc_bit_size);
 
   for (unsigned short i = 0; i < data_size; i++)
     {
       /* crc >> (crc_bit_size - 8).  */
-      *crc = force_reg (crc_mode, *crc);
+      *crc = force_reg (mode, *crc);
       rtx op1 = expand_shift (RSHIFT_EXPR, mode, *crc, crc_bit_size - 8,
 			      NULL_RTX, 1);
 
       /* data >> (8 * (GET_MODE_SIZE (data_mode).to_constant () - i - 1)).  */
       unsigned range_8 = 8 * (data_size - i - 1);
-      rtx data = force_reg (data_mode, input_data);
+      /* CRC's mode is always at least as wide as INPUT_DATA.  Convert
+	 INPUT_DATA into CRC's mode.  */
+      rtx data = gen_reg_rtx (mode);
+      convert_move (data, input_data, 1);
       data = expand_shift (RSHIFT_EXPR, mode, data, range_8, NULL_RTX, 1);
 
-      /* data >> (8 * (GET_MODE_SIZE (data_mode)
+      /* data >> (8 * (GET_MODE_SIZE (mode)
 					.to_constant () - i - 1)) & 0xFF.  */
       rtx data_final = expand_and (mode, data,
-				   gen_int_mode (255, data_mode), NULL_RTX);
+				   gen_int_mode (255, mode), NULL_RTX);
 
       /* (crc >> (crc_bit_size - 8)) ^ data_8bit.  */
       rtx in = expand_binop (mode, xor_optab, op1, data_final,
@@ -14367,7 +14370,7 @@ calculate_table_based_CRC (rtx *crc, const rtx &input_data,
       /* ((crc >> (crc_bit_size - 8)) ^ data_8bit) & 0xFF.  */
       rtx index = expand_and (mode, in, gen_int_mode (255, mode),
 			      NULL_RTX);
-      int log_crc_size = exact_log2 (GET_MODE_SIZE (crc_mode).to_constant ());
+      int log_crc_size = exact_log2 (GET_MODE_SIZE (mode).to_constant ());
       index = expand_shift (LSHIFT_EXPR, mode, index,
 			    log_crc_size, NULL_RTX, 0);
 
@@ -14377,7 +14380,7 @@ calculate_table_based_CRC (rtx *crc, const rtx &input_data,
 			    0, OPTAB_DIRECT);
 
       /* crc_table[(crc >> (crc_bit_size - 8)) ^ data_8bit]  */
-      rtx tab_el = validize_mem (gen_rtx_MEM (crc_mode, addr));
+      rtx tab_el = validize_mem (gen_rtx_MEM (mode, addr));
 
       /* (crc << 8) if CRC is larger than 8, otherwise crc = 0.  */
       rtx high = NULL_RTX;
@@ -14420,7 +14423,7 @@ expand_crc_table_based (rtx op0, rtx op1, rtx op2, rtx op3,
   machine_mode crc_mode = GET_MODE (op0);
   rtx crc = gen_reg_rtx (crc_mode);
   convert_move (crc, op1, 0);
-  calculate_table_based_CRC (&crc, op2, op3, crc_mode, data_mode);
+  calculate_table_based_CRC (&crc, op2, op3, data_mode);
   convert_move (op0, crc, 0);
 }
 
@@ -14563,7 +14566,7 @@ expand_reversed_crc_table_based (rtx op0, rtx op1, rtx op2, rtx op3,
   convert_move (data, op2, 0);
   gen_reflecting_code (&data);
 
-  calculate_table_based_CRC (&crc, data, op3, crc_mode, data_mode);
+  calculate_table_based_CRC (&crc, data, op3, data_mode);
 
   gen_reflecting_code (&crc);
   convert_move (op0, crc, 0);