re PR target/86731 (Miscompiles vec_sl at -O3 with -fwrapv on ppc64el)

[gcc]

2018-09-06  Will Schmidt  <will_schmidt@vnet.ibm.com>

	PR target/86731
	* config/rs6000/rs6000.c (rs6000_gimple_fold_builtin): Update logic
	around folding of vec_sl to handle out of range shift values.

[testsuite]

2018-08-15  Will Schmidt  <will_schmidt@vnet.ibm.com>

	PR target/86731
	* gcc.target/powerpc/pr86731.c: New test.
	* gcc.target/powerpc/pr86731-longlong.c: New test.
	* gcc.target/powerpc/pr86731-fwrapv.c: New test.
	* gcc.target/powerpc/pr86731-fwrapv-longlong.c: New test.
	* gcc.target/powerpc/pr86731-nogimplefold.c: New test.
	* gcc.target/powerpc/pr86731-nogimplefold-longlong.c: New test.

From-SVN: r264150

gcc/ChangeLog

@@ -1,3 +1,9 @@
+2018-09-06  Will Schmidt  <will_schmidt@vnet.ibm.com>
+
+	PR target/86731
+	* config/rs6000/rs6000.c (rs6000_gimple_fold_builtin): Update logic
+	around folding of vec_sl to handle out of range shift values.
+
 2018-09-06  Uros Bizjak  <ubizjak@gmail.com>
 
 	* config/i386/i386.md (fix_trunc<mode>_fisttp_i387_1): Remove.

gcc/config/rs6000/rs6000.c

@@ -15487,16 +15487,44 @@ rs6000_gimple_fold_builtin (gimple_stmt_iterator *gsi)
     case ALTIVEC_BUILTIN_VSLH:
     case ALTIVEC_BUILTIN_VSLW:
     case P8V_BUILTIN_VSLD:
+      {
+	location_t loc;
+	gimple_seq stmts = NULL;
 	arg0 = gimple_call_arg (stmt, 0);
-      if (INTEGRAL_TYPE_P (TREE_TYPE (TREE_TYPE (arg0)))
+	tree arg0_type = TREE_TYPE (arg0);
-	  && !TYPE_OVERFLOW_WRAPS (TREE_TYPE (TREE_TYPE (arg0))))
+	if (INTEGRAL_TYPE_P (TREE_TYPE (arg0_type))
+	    && !TYPE_OVERFLOW_WRAPS (TREE_TYPE (arg0_type)))
 	  return false;
 	arg1 = gimple_call_arg (stmt, 1);
+	tree arg1_type = TREE_TYPE (arg1);
+	tree unsigned_arg1_type = unsigned_type_for (TREE_TYPE (arg1));
+	tree unsigned_element_type = unsigned_type_for (TREE_TYPE (arg1_type));
+	loc = gimple_location (stmt);
 	lhs = gimple_call_lhs (stmt);
-      g = gimple_build_assign (lhs, LSHIFT_EXPR, arg0, arg1);
+	/* Force arg1 into the range valid matching the arg0 type.  */
+	/* Build a vector consisting of the max valid bit-size values.  */
+	int n_elts = VECTOR_CST_NELTS (arg1);
+	int tree_size_in_bits = TREE_INT_CST_LOW (size_in_bytes (arg1_type))
+				* BITS_PER_UNIT;
+	tree element_size = build_int_cst (unsigned_element_type,
+					   tree_size_in_bits / n_elts);
+	tree_vector_builder elts (unsigned_type_for (arg1_type), n_elts, 1);
+	for (int i = 0; i < n_elts; i++)
+	  elts.safe_push (element_size);
+	tree modulo_tree = elts.build ();
+	/* Modulo the provided shift value against that vector.  */
+	tree unsigned_arg1 = gimple_build (&stmts, VIEW_CONVERT_EXPR,
+					   unsigned_arg1_type, arg1);
+	tree new_arg1 = gimple_build (&stmts, loc, TRUNC_MOD_EXPR,
+				      unsigned_arg1_type, unsigned_arg1,
+				      modulo_tree);
+	gsi_insert_seq_before (gsi, stmts, GSI_SAME_STMT);
+	/* And finally, do the shift.  */
+	g = gimple_build_assign (lhs, LSHIFT_EXPR, arg0, new_arg1);
 	gimple_set_location (g, gimple_location (stmt));
 	gsi_replace (gsi, g, true);
 	return true;
+      }
     /* Flavors of vector shift right.  */
     case ALTIVEC_BUILTIN_VSRB:
     case ALTIVEC_BUILTIN_VSRH:

gcc/testsuite/ChangeLog

@@ -1,3 +1,13 @@
+2018-09-06  Will Schmidt  <will_schmidt@vnet.ibm.com>
+
+	PR target/86731
+	* gcc.target/powerpc/pr86731.c: New test.
+	* gcc.target/powerpc/pr86731-longlong.c: New test.
+	* gcc.target/powerpc/pr86731-fwrapv.c: New test.
+	* gcc.target/powerpc/pr86731-fwrapv-longlong.c: New test.
+	* gcc.target/powerpc/pr86731-nogimplefold.c: New test.
+	* gcc.target/powerpc/pr86731-nogimplefold-longlong.c: New test.
+
 2018-09-06  Ilya Leoshkevich  <iii@linux.ibm.com>
 
 	PR target/80080

gcc/testsuite/gcc.target/powerpc/pr86731-fwrapv-longlong.c

@@ -0,0 +1,34 @@
+/* PR86731.  Verify that the rs6000 gimple-folding code handles the
+   left shift operation properly.  This is a testcase variation that
+   explicitly specifies -fwrapv, which is a condition for the
+   gimple folding of the vec_sl() intrinsic.  */
+
+/* specify -mpower8-vector, which provides vec_sl(long long,...) support. */
+
+/* { dg-do compile } */
+/* { dg-require-effective-target powerpc_p8vector_ok } */
+/* { dg-require-effective-target lp64 } */
+/* { dg-options "-maltivec -O3 -fwrapv -mpower8-vector " } */
+
+#include <altivec.h>
+
+vector unsigned long long splatu4(void)
+{
+        vector unsigned long long mzero = {-1,-1};
+        return (vector unsigned long long) vec_sl(mzero, mzero);
+}
+
+vector signed long long splats4(void)
+{
+        vector unsigned long long mzero = {-1,-1};
+        return (vector signed long long) vec_sl(mzero, mzero);
+}
+
+/* Codegen will consist of splat and shift instructions for most types.
+   If folding is enabled, the vec_sl tests using vector long long type will
+   generate a lvx instead of a vspltisw+vsld pair.  */
+
+/* { dg-final { scan-assembler-times {\mvspltis[bhw]\M} 0 } } */
+/* { dg-final { scan-assembler-times {\mvsl[bhwd]\M} 0 } } */
+/* { dg-final { scan-assembler-times {\mlvx\M|\mlxv\M|\mlxvd2x\M} 2 } } */
+

gcc/testsuite/gcc.target/powerpc/pr86731-fwrapv.c

@@ -0,0 +1,63 @@
+/* PR86731.  Verify that the rs6000 gimple-folding code handles the
+   left shift operation properly.  This is a testcase variation that
+   explicitly specifies -fwrapv, which is a condition for the
+   gimple folding of the vec_sl() intrinsic.  */
+
+/* { dg-do compile } */
+/* { dg-require-effective-target powerpc_altivec_ok } */
+/* { dg-require-effective-target lp64 } */
+/* { dg-options "-maltivec -O3 -fwrapv " } */
+
+#include <altivec.h>
+/* original test as reported.  */
+vector unsigned int splat(void)
+{
+        vector unsigned int mzero = vec_splat_u32(-1);
+        return (vector unsigned int) vec_sl(mzero, mzero);
+}
+
+/* more testcase variations.  */
+vector unsigned char splatu1(void)
+{
+        vector unsigned char mzero = vec_splat_u8(-1);
+        return (vector unsigned char) vec_sl(mzero, mzero);
+}
+
+vector unsigned short splatu2(void)
+{
+        vector unsigned short mzero = vec_splat_u16(-1);
+        return (vector unsigned short) vec_sl(mzero, mzero);
+}
+
+vector unsigned int splatu3(void)
+{
+        vector unsigned int mzero = vec_splat_u32(-1);
+        return (vector unsigned int) vec_sl(mzero, mzero);
+}
+
+vector signed char splats1(void)
+{
+        vector unsigned char mzero = vec_splat_u8(-1);
+        return (vector signed char) vec_sl(mzero, mzero);
+}
+
+vector signed short splats2(void)
+{
+        vector unsigned short mzero = vec_splat_u16(-1);
+        return (vector signed short) vec_sl(mzero, mzero);
+}
+
+vector signed int splats3(void)
+{
+        vector unsigned int mzero = vec_splat_u32(-1);
+        return (vector signed int) vec_sl(mzero, mzero);
+}
+
+/* Codegen will consist of splat and shift instructions.
+   If folding is enabled, the vec_sl tests using vector long long type will
+   generate a lvx instead of a vspltisw+vsld pair.  */
+
+/* { dg-final { scan-assembler-times {\mvspltis[bhw]\M|\mxxspltib\M} 7 } } */
+/* { dg-final { scan-assembler-times {\mvsl[bhwd]\M} 7 } } */
+/* { dg-final { scan-assembler-times {\mlvx\M|\mlxvd2x\M} 0 } } */
+

gcc/testsuite/gcc.target/powerpc/pr86731-longlong.c

@@ -0,0 +1,29 @@
+/* PR86731.  Verify that the rs6000 gimple-folding code handles the
+   left shift properly.  */
+
+/* { dg-do compile } */
+/* { dg-require-effective-target powerpc_p8vector_ok } */
+/* { dg-require-effective-target lp64 } */
+/* { dg-options "-maltivec -O3 -mpower8-vector " } */
+
+#include <altivec.h>
+
+vector unsigned long long splatu4(void)
+{
+        vector unsigned long long mzero = {-1,-1};
+        return (vector unsigned long long) vec_sl(mzero, mzero);
+}
+vector signed long long splats4(void)
+{
+        vector unsigned long long mzero = {-1,-1};
+        return (vector signed long long) vec_sl(mzero, mzero);
+}
+
+/* Codegen will consist of splat and shift instructions for most types.
+   Noted variations:  if gimple folding is disabled, or if -fwrapv is not
+   specified, the long long tests will generate a vspltisw+vsld pair,
+   versus generating a single lvx.  */
+/* { dg-final { scan-assembler-times {\mvspltis[bhw]\M|\mxxspltib\M} 2 } } */
+/* { dg-final { scan-assembler-times {\mvsl[bhwd]\M} 2 } } */
+/* { dg-final { scan-assembler-times {\mlvx\M} 0 } } */
+

gcc/testsuite/gcc.target/powerpc/pr86731-nogimplefold-longlong.c

@@ -0,0 +1,32 @@
+/* PR86731.  Verify that the rs6000 gimple-folding code handles the
+   left shift operation properly.  This is a testcase variation that
+   explicitly disables gimple folding.  */
+
+/* { dg-do compile } */
+/* { dg-require-effective-target powerpc_p8vector_ok } */
+/* { dg-require-effective-target lp64 } */
+/* { dg-options "-maltivec -O3 -fwrapv -mno-fold-gimple -mpower8-vector " } */
+/* { dg-prune-output "gimple folding of rs6000 builtins has been disabled." } */
+
+
+#include <altivec.h>
+
+vector unsigned long long splatu4(void)
+{
+        vector unsigned long long mzero = {-1,-1};
+        return (vector unsigned long long) vec_sl(mzero, mzero);
+}
+
+vector signed long long splats4(void)
+{
+        vector unsigned long long mzero = {-1,-1};
+        return (vector signed long long) vec_sl(mzero, mzero);
+}
+
+/* Codegen will consist of splat and shift instructions for most types.
+   Noted variations:  if gimple folding is disabled, or if -fwrapv is not specified, the
+   long long tests will generate a vspltisw+vsld pair, versus generating a lvx.  */
+/* { dg-final { scan-assembler-times {\mvspltis[bhw]\M|\mxxspltib\M} 2 } } */
+/* { dg-final { scan-assembler-times {\mvsl[bhwd]\M} 2 } } */
+/* { dg-final { scan-assembler-times {\mlvx\M} 0 } } */
+

gcc/testsuite/gcc.target/powerpc/pr86731-nogimplefold.c

@@ -0,0 +1,63 @@
+/* PR86731.  Verify that the rs6000 gimple-folding code handles the
+   left shift operation properly.  This is a testcase variation that
+   explicitly disables gimple folding.  */
+
+/* { dg-do compile } */
+/* { dg-require-effective-target powerpc_altivec_ok } */
+/* { dg-require-effective-target lp64 } */
+/* { dg-options "-maltivec -O3 -fwrapv -mno-fold-gimple" } */
+/* { dg-prune-output "gimple folding of rs6000 builtins has been disabled." } */
+
+
+#include <altivec.h>
+/* original test as reported.  */
+vector unsigned int splat(void)
+{
+        vector unsigned int mzero = vec_splat_u32(-1);
+        return (vector unsigned int) vec_sl(mzero, mzero);
+}
+
+/* more testcase variations.  */
+vector unsigned char splatu1(void)
+{
+        vector unsigned char mzero = vec_splat_u8(-1);
+        return (vector unsigned char) vec_sl(mzero, mzero);
+}
+
+vector unsigned short splatu2(void)
+{
+        vector unsigned short mzero = vec_splat_u16(-1);
+        return (vector unsigned short) vec_sl(mzero, mzero);
+}
+
+vector unsigned int splatu3(void)
+{
+        vector unsigned int mzero = vec_splat_u32(-1);
+        return (vector unsigned int) vec_sl(mzero, mzero);
+}
+
+vector signed char splats1(void)
+{
+        vector unsigned char mzero = vec_splat_u8(-1);
+        return (vector signed char) vec_sl(mzero, mzero);
+}
+
+vector signed short splats2(void)
+{
+        vector unsigned short mzero = vec_splat_u16(-1);
+        return (vector signed short) vec_sl(mzero, mzero);
+}
+
+vector signed int splats3(void)
+{
+        vector unsigned int mzero = vec_splat_u32(-1);
+        return (vector signed int) vec_sl(mzero, mzero);
+}
+
+/* Codegen will consist of splat and shift instructions for most types.
+   Noted variations:  if gimple folding is disabled, or if -fwrapv is not specified, the
+   long long tests will generate a vspltisw+vsld pair, versus generating a lvx.  */
+/* { dg-final { scan-assembler-times {\mvspltis[bhw]\M|\mxxspltib\M} 7 } } */
+/* { dg-final { scan-assembler-times {\mvsl[bhwd]\M} 7 } } */
+/* { dg-final { scan-assembler-times {\mlvx\M} 0 } } */
+

gcc/testsuite/gcc.target/powerpc/pr86731.c

@@ -0,0 +1,61 @@
+/* PR86731.  Verify that the rs6000 gimple-folding code handles the
+   left shift properly.  */
+
+/* { dg-do compile } */
+/* { dg-require-effective-target powerpc_altivec_ok } */
+/* { dg-require-effective-target lp64 } */
+/* { dg-options "-maltivec -O3" } */
+
+#include <altivec.h>
+/* The original test as reported.  */
+vector unsigned int splat(void)
+{
+        vector unsigned int mzero = vec_splat_u32(-1);
+        return (vector unsigned int) vec_sl(mzero, mzero);
+}
+
+/* more testcase variations.  */
+vector unsigned char splatu1(void)
+{
+        vector unsigned char mzero = vec_splat_u8(-1);
+        return (vector unsigned char) vec_sl(mzero, mzero);
+}
+
+vector unsigned short splatu2(void)
+{
+        vector unsigned short mzero = vec_splat_u16(-1);
+        return (vector unsigned short) vec_sl(mzero, mzero);
+}
+
+vector unsigned int splatu3(void)
+{
+        vector unsigned int mzero = vec_splat_u32(-1);
+        return (vector unsigned int) vec_sl(mzero, mzero);
+}
+
+vector signed char splats1(void)
+{
+        vector unsigned char mzero = vec_splat_u8(-1);
+        return (vector signed char) vec_sl(mzero, mzero);
+}
+
+vector signed short splats2(void)
+{
+        vector unsigned short mzero = vec_splat_u16(-1);
+        return (vector signed short) vec_sl(mzero, mzero);
+}
+
+vector signed int splats3(void)
+{
+        vector unsigned int mzero = vec_splat_u32(-1);
+        return (vector signed int) vec_sl(mzero, mzero);
+}
+
+/* Codegen will consist of splat and shift instructions for most types.
+   Noted variations:  if gimple folding is disabled, or if -fwrapv is not
+   specified, the long long tests will generate a vspltisw+vsld pair,
+   versus generating a single lvx.  */
+/* { dg-final { scan-assembler-times {\mvspltis[bhw]\M|\mxxspltib\M} 7 } } */
+/* { dg-final { scan-assembler-times {\mvsl[bhwd]\M} 7 } } */
+/* { dg-final { scan-assembler-times {\mlvx\M} 0 } } */
+