From: Segher Boessenkool <segher@kernel.crashing.org>
Date: Tue, 3 Oct 2017 16:02:38 +0000 (+0200)
Subject: simplify-rtx: Remove non-simplifying simplification (PR77729)
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=a8ccdfa8ea6fbdc78bdd5617427d7ba945cc83af;p=gcc.git

simplify-rtx: Remove non-simplifying simplification (PR77729)

If we have (X&C1)|C2 simplify_binary_operation_1 makes C1 as small as
possible.  This makes worse code in common cases like when the AND with
C1 is from a zero-extension.  This patch fixes it by removing this
transformation (twice).


	PR rtl-optimization/77729
	* simplify-rtx.c (simplify_binary_operation_1): Delete the (X&C1)|C2
	to (X&(C1&~C2))|C2 transformations.

From-SVN: r253384
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 33ae1be901a..9d43ae54b69 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2017-10-03  Segher Boessenkool  <segher@kernel.crashing.org>
+
+	PR rtl-optimization/77729
+	* simplify-rtx.c (simplify_binary_operation_1): Delete the (X&C1)|C2
+	to (X&(C1&~C2))|C2 transformations.
+
 2017-10-03  Martin Jambor  <mjambor@suse.cz>
 
 	PR tree-optimization/82363
diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c
index 1b960b91c0c..3b6cf6fa850 100644
--- a/gcc/simplify-rtx.c
+++ b/gcc/simplify-rtx.c
@@ -2673,14 +2673,6 @@ simplify_binary_operation_1 (enum rtx_code code, machine_mode mode,
 	  /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2.  */
 	  if (((c1|c2) & mask) == mask)
 	    return simplify_gen_binary (IOR, mode, XEXP (op0, 0), op1);
-
-	  /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2.  */
-	  if (((c1 & ~c2) & mask) != (c1 & mask))
-	    {
-	      tem = simplify_gen_binary (AND, mode, XEXP (op0, 0),
-					 gen_int_mode (c1 & ~c2, mode));
-	      return simplify_gen_binary (IOR, mode, tem, op1);
-	    }
 	}
 
       /* Convert (A & B) | A to A.  */
@@ -2736,23 +2728,6 @@ simplify_binary_operation_1 (enum rtx_code code, machine_mode mode,
 	return gen_rtx_ROTATE (int_mode, XEXP (opright, 0),
 			       XEXP (SUBREG_REG (opleft), 1));
 
-      /* If we have (ior (and (X C1) C2)), simplify this by making
-	 C1 as small as possible if C1 actually changes.  */
-      if (CONST_INT_P (op1)
-	  && (HWI_COMPUTABLE_MODE_P (mode)
-	      || INTVAL (op1) > 0)
-	  && GET_CODE (op0) == AND
-	  && CONST_INT_P (XEXP (op0, 1))
-	  && CONST_INT_P (op1)
-	  && (UINTVAL (XEXP (op0, 1)) & UINTVAL (op1)) != 0)
-	{
-	  rtx tmp = simplify_gen_binary (AND, mode, XEXP (op0, 0),
-					 gen_int_mode (UINTVAL (XEXP (op0, 1))
-						       & ~UINTVAL (op1),
-						       mode));
-	  return simplify_gen_binary (IOR, mode, tmp, op1);
-	}
-
       /* If OP0 is (ashiftrt (plus ...) C), it might actually be
          a (sign_extend (plus ...)).  Then check if OP1 is a CONST_INT and
 	 the PLUS does not affect any of the bits in OP1: then we can do