@@ -415,6 +415,15 @@ riscv_build_integer_1 (struct riscv_integer_op codes[RISCV_MAX_INTEGER_OPS],
/* Simply BSETI. */
codes[0].code = UNKNOWN;
codes[0].value = value;
+
+ /* RISC-V sign-extends all 32bit values that life in a 32bit
+ register. To avoid paradoxes, we thus need to use the
+ sign-extended (negative) representation for the value, if we
+ want to build 0x80000000 in SImode. This will then expand
+ to an ADDI/LI instruction. */
+ if (mode == SImode && value == 0x80000000)
+ codes[0].value = -2147483648;
+
return 1;
}
@@ -526,13 +526,10 @@ enum reg_class
(((VALUE) | ((1UL<<31) - IMM_REACH)) == ((1UL<<31) - IMM_REACH) \
|| ((VALUE) | ((1UL<<31) - IMM_REACH)) + IMM_REACH == 0)
-/* If this is a single bit mask, then we can load it with bseti. But this
- is not useful for any of the low 31 bits because we can use addi or lui
- to load them. It is wrong for loading SImode 0x80000000 on rv64 because it
- needs to be sign-extended. So we restrict this to the upper 32-bits
- only. */
-#define SINGLE_BIT_MASK_OPERAND(VALUE) \
- (pow2p_hwi (VALUE) && (ctz_hwi (VALUE) >= 32))
+/* If this is a single bit mask, then we can load it with bseti. Special
+ handling of SImode 0x80000000 on RV64 is done in riscv_build_integer_1. */
+#define SINGLE_BIT_MASK_OPERAND(VALUE) \
+ (pow2p_hwi (VALUE))
/* Stack layout; function entry, exit and calling. */
The SINGLE_BIT_MASK_OPERAND() is overly restrictive, triggering for bits above 31 only (to side-step any issues with the negative SImode value 0x80000000). This moves the special handling of this SImode value (i.e. the check for -2147483648) to riscv.c and relaxes the SINGLE_BIT_MASK_OPERAND() test. This changes the code-generation for loading (1ULL << 31) from: li a0,1 slli a0,a0,31 to: bseti a0,zero,31 gcc/ChangeLog: * config/riscv/riscv.c (riscv_build_integer_1): Rewrite value as -2147483648 for the single-bit case, when operating on 0x80000000 in SImode. * gcc/config/riscv/riscv.h (SINGLE_BIT_MASK_OPERAND): Allow for any single-bit value, moving the special case for 0x80000000 to riscv_build_integer_1 (in riscv.c). Signed-off-by: Philipp Tomsich <philipp.tomsich@vrull.eu> --- gcc/config/riscv/riscv.c | 9 +++++++++ gcc/config/riscv/riscv.h | 11 ++++------- 2 files changed, 13 insertions(+), 7 deletions(-)