[gcc r12-3130] [Committed] PR middle-end/102031: Fix typo/mistake in simplify_truncation patch.

[gcc r12-3130] [Committed] PR middle-end/102031: Fix typo/mistake in simplify_truncation patch.

[Roger Sayle]

https://gcc.gnu.org/g:81e1894456bc6214c0c42148ff2b1bed142a3545

commit r12-3130-g81e1894456bc6214c0c42148ff2b1bed142a3545
Author: Roger Sayle <roger@nextmovesoftware.com>
Date:   Tue Aug 24 22:07:41 2021 +0100

    [Committed] PR middle-end/102031: Fix typo/mistake in simplify_truncation patch.
    
    My apologies again.  My patch to simplify truncations of SUBREGs in
    simplify-rtx.c contained an error where I'd accidentally compared
    against a mode instead of the precision of that mode.  Grr!  It even
    survived regression testing on two platforms.  Fixed below, and
    committed as obvious, after a full "make bootstrap" and "make -k check"
    on x86_64-pc-linux-gnu with no new regressions.
    
    2021-08-24  Roger Sayle  <roger@nextmovesoftware.com>
    
    gcc/ChangeLog
            PR middle-end/102031
            * simplify-rtx.c (simplify_truncation): When comparing precisions
            use "subreg_prec" variable, not "subreg_mode".

Diff:
---
 gcc/simplify-rtx.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c
index 8eea9fb7e0a..c81e27eb008 100644
--- a/gcc/simplify-rtx.c
+++ b/gcc/simplify-rtx.c
@@ -841,7 +841,7 @@ simplify_context::simplify_truncation (machine_mode mode, rtx op,
 	{
 	  unsigned int int_op_prec = GET_MODE_PRECISION (int_op_mode);
 	  unsigned int subreg_prec = GET_MODE_PRECISION (subreg_mode);
-	  if (int_op_prec > subreg_mode)
+	  if (int_op_prec > subreg_prec)
 	    {
 	      if (int_mode == subreg_mode)
 		return SUBREG_REG (op);
@@ -851,7 +851,7 @@ simplify_context::simplify_truncation (machine_mode mode, rtx op,
 	    }
 	  /* Simplification of (truncate:A (subreg:B X:C 0)) where
  	     A is narrower than B and B is narrower than C.  */
-	  else if (int_op_prec < subreg_mode
+	  else if (int_op_prec < subreg_prec
 		   && GET_MODE_PRECISION (int_mode) < int_op_prec)
 	    return simplify_gen_unary (TRUNCATE, int_mode,
 				       SUBREG_REG (op), subreg_mode);