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Re: gas signed overflow fixes

On Thu, 12 Dec 2019 03:10:15 PST (-0800), amodra@gmail.com wrote:

diff --git a/gas/config/tc-riscv.c b/gas/config/tc-riscv.c
index 055d80c344..7ec1028b28 100644
--- a/gas/config/tc-riscv.c
+++ b/gas/config/tc-riscv.c
@@ -1043,9 +1043,9 @@ static void
 load_const (int reg, expressionS *ep)
 {
   int shift = RISCV_IMM_BITS;
-  bfd_vma upper_imm;
+  bfd_vma upper_imm, sign = (bfd_vma) 1 << (RISCV_IMM_BITS - 1);
   expressionS upper = *ep, lower = *ep;
-  lower.X_add_number = (int32_t) ep->X_add_number << (32-shift) >> (32-shift);
+  lower.X_add_number = ((ep->X_add_number & (sign + sign - 1)) ^ sign) - sign;
   upper.X_add_number -= lower.X_add_number;

   if (ep->X_op != O_constant)


Thanks!
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