re PR target/44551 ([missed optimization] AVX vextractf128 after vinsertf128)

2014-07-26  Marc Glisse  <marc.glisse@inria.fr>

	PR target/44551
gcc/
	* simplify-rtx.c (simplify_binary_operation_1) <VEC_SELECT>:
	Optimize inverse of a VEC_CONCAT.
gcc/testsuite/
	* gcc.target/i386/pr44551-1.c: New file.

From-SVN: r213076

gcc/ChangeLog

+2014-07-26  Marc Glisse  <marc.glisse@inria.fr>
+
+	PR target/44551
+	* simplify-rtx.c (simplify_binary_operation_1) <VEC_SELECT>:
+	Optimize inverse of a VEC_CONCAT.
+
 2014-07-25  Xinliang David Li  <davidxl@google.com>
 
 	* params.def: New parameter.

gcc/simplify-rtx.c

@@ -3368,6 +3368,50 @@ simplify_binary_operation_1 (enum rtx_code code, enum machine_mode mode,
 
 	      return simplify_gen_binary (VEC_CONCAT, mode, subop0, subop1);
 	    }
+
+	  /* If we select one half of a vec_concat, return that.  */
+	  if (GET_CODE (trueop0) == VEC_CONCAT
+	      && CONST_INT_P (XVECEXP (trueop1, 0, 0)))
+	    {
+	      rtx subop0 = XEXP (trueop0, 0);
+	      rtx subop1 = XEXP (trueop0, 1);
+	      enum machine_mode mode0 = GET_MODE (subop0);
+	      enum machine_mode mode1 = GET_MODE (subop1);
+	      int li = GET_MODE_SIZE (GET_MODE_INNER (mode0));
+	      int l0 = GET_MODE_SIZE (mode0) / li;
+	      int l1 = GET_MODE_SIZE (mode1) / li;
+	      int i0 = INTVAL (XVECEXP (trueop1, 0, 0));
+	      if (i0 == 0 && !side_effects_p (op1) && mode == mode0)
+		{
+		  bool success = true;
+		  for (int i = 1; i < l0; ++i)
+		    {
+		      rtx j = XVECEXP (trueop1, 0, i);
+		      if (!CONST_INT_P (j) || INTVAL (j) != i)
+			{
+			  success = false;
+			  break;
+			}
+		    }
+		  if (success)
+		    return subop0;
+		}
+	      if (i0 == l0 && !side_effects_p (op0) && mode == mode1)
+		{
+		  bool success = true;
+		  for (int i = 1; i < l1; ++i)
+		    {
+		      rtx j = XVECEXP (trueop1, 0, i);
+		      if (!CONST_INT_P (j) || INTVAL (j) != i0 + i)
+			{
+			  success = false;
+			  break;
+			}
+		    }
+		  if (success)
+		    return subop1;
+		}
+	    }
 	}
 
       if (XVECLEN (trueop1, 0) == 1

gcc/testsuite/ChangeLog

+2014-07-26  Marc Glisse  <marc.glisse@inria.fr>
+
+	PR target/44551
+	* gcc.target/i386/pr44551-1.c: New file.
+
 2014-07-25  Xinliang David Li  <davidxl@google.com>
 
 	* g++.dg/tree-prof/tree-prof.exp: Define macros.

gcc/testsuite/gcc.target/i386/pr44551-1.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -mavx" } */
+
+#include <immintrin.h>
+
+__m128i
+foo (__m256i x, __m128i y)
+{
+  __m256i r = _mm256_insertf128_si256(x, y, 1);
+  __m128i a = _mm256_extractf128_si256(r, 1);
+  return a;
+}
+
+/* { dg-final { scan-assembler-not "vinsertf" } } */
+/* { dg-final { scan-assembler-not "vextractf" } } */