Index: gcc/config/rs6000/rs6000.c
===================================================================
--- gcc/config/rs6000/rs6000.c	(revision 277550)
+++ gcc/config/rs6000/rs6000.c	(working copy)
@@ -1428,6 +1428,9 @@ static const struct attribute_spec rs6000_attribut
 #undef TARGET_VECTORIZE_DESTROY_COST_DATA
 #define TARGET_VECTORIZE_DESTROY_COST_DATA rs6000_destroy_cost_data
 
+#undef TARGET_LOOP_UNROLL_ADJUST
+#define TARGET_LOOP_UNROLL_ADJUST rs6000_loop_unroll_adjust
+
 #undef TARGET_INIT_BUILTINS
 #define TARGET_INIT_BUILTINS rs6000_init_builtins
 #undef TARGET_BUILTIN_DECL
@@ -4540,20 +4543,11 @@ rs6000_option_override_internal (bool global_init_
 			     global_options.x_param_values,
 			     global_options_set.x_param_values);
 
-      /* unroll very small loops 2 time if no -funroll-loops.  */
+      /* If funroll-loops is implicitly enabled, do not turn fweb or
+	 frename-registers on implicitly.  */
       if (!global_options_set.x_flag_unroll_loops
 	  && !global_options_set.x_flag_unroll_all_loops)
 	{
-	  maybe_set_param_value (PARAM_MAX_UNROLL_TIMES, 2,
-				 global_options.x_param_values,
-				 global_options_set.x_param_values);
-
-	  maybe_set_param_value (PARAM_MAX_UNROLLED_INSNS, 20,
-				 global_options.x_param_values,
-				 global_options_set.x_param_values);
-
-	  /* If fweb or frename-registers are not specificed in command-line,
-	     do not turn them on implicitly.  */
 	  if (!global_options_set.x_flag_web)
 	    global_options.x_flag_web = 0;
 	  if (!global_options_set.x_flag_rename_registers)
@@ -5101,6 +5095,29 @@ rs6000_destroy_cost_data (void *data)
   free (data);
 }
 
+/* This target hook implementation for TARGET_LOOP_UNROLL_ADJUST calculates
+   a new heristic number struct loop *loop should be unrolled.  */
+
+static unsigned
+rs6000_loop_unroll_adjust (unsigned nunroll, struct loop * loop)
+{
+  /* If funroll-loops was enabled implicitly, like at -O2, we only unroll
+     those small loops with small unroll factor.  */
+  if (!global_options_set.x_flag_unroll_loops
+      && !global_options_set.x_flag_unroll_all_loops)
+    {
+      /* If the loop contains few insns, treated it as small loops.
+	 TODO: Uing 10 hard code for now.  Continue to refine, For example,
+	 if loop constians only 1-2 insns, we may unroll more times(4).
+	 And we may use PARAM to control kinds of loop size.  */
+      if (loop->ninsns <= 10)
+	return 2;
+      else
+	return 0;
+    }
+  return nunroll;
+}
+
 /* Handler for the Mathematical Acceleration Subsystem (mass) interface to a
    library with vectorized intrinsics.  */
 
Index: gcc/testsuite/gcc.dg/pr59643.c
===================================================================
--- gcc/testsuite/gcc.dg/pr59643.c	(revision 277550)
+++ gcc/testsuite/gcc.dg/pr59643.c	(working copy)
@@ -1,9 +1,6 @@
 /* PR tree-optimization/59643 */
 /* { dg-do compile } */
 /* { dg-options "-O3 -fdump-tree-pcom-details" } */
-/* { dg-additional-options "--param max-unrolled-insns=400" { target { powerpc*-*-* } } } */
-/* Implicit threashold of max-unrolled-insn on ppc at O3 is too small for the
-   loop of this case.  */
 
 void
 foo (double *a, double *b, double *c, double d, double e, int n)


-------- combined patch---------
gcc/ChangeLog
2019-10-25  Jiufu Guo  <guojiufu@linux.ibm.com>	    

	PR tree-optimization/88760
	* config/rs6000/rs6000-common.c (rs6000_option_optimization_table):
	Enable -funroll-loops for -O2 and above.
	* config/rs6000/rs6000.c (rs6000_option_override_internal): Avoid turn
	on web and rnreg implicitly.
	(TARGET_LOOP_UNROLL_ADJUST): Add loop unroll adjust hook.
	(rs6000_loop_unroll_adjust): New hook for loop unroll adjust. Unrolling
	small loop 2 times if funroll-loops enabled implicitly.


gcc/testsuite/ChangeLog
2019-10-25  Jiufu Guo  <guojiufu@linux.ibm.com>

	PR tree-optimization/88760
	* gcc.target/powerpc/small-loop-unroll.c: New test.
	* c-c++-common/tsan/thread_leak2.c: Update test.
	* gcc.target/powerpc/loop_align.c: Update test.
	* gcc.target/powerpc/ppc-fma-1.c: Update test.
	* gcc.target/powerpc/ppc-fma-2.c: Update test.
	* gcc.target/powerpc/ppc-fma-3.c: Update test.
	* gcc.target/powerpc/ppc-fma-4.c: Update test.
	* gcc.target/powerpc/pr78604.c: Update test.


diff --git a/gcc/common/config/rs6000/rs6000-common.c b/gcc/common/config/rs6000/rs6000-common.c
index 4b0c205..b947196 100644
--- a/gcc/common/config/rs6000/rs6000-common.c
+++ b/gcc/common/config/rs6000/rs6000-common.c
@@ -35,6 +35,7 @@ static const struct default_options rs6000_option_optimization_table[] =
     { OPT_LEVELS_ALL, OPT_fsplit_wide_types_early, NULL, 1 },
     /* Enable -fsched-pressure for first pass instruction scheduling.  */
     { OPT_LEVELS_1_PLUS, OPT_fsched_pressure, NULL, 1 },
+    { OPT_LEVELS_2_PLUS, OPT_funroll_loops, NULL, 1 },
     { OPT_LEVELS_NONE, 0, NULL, 0 }
   };
 
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 1399221..28ffa15 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -1428,6 +1428,9 @@ static const struct attribute_spec rs6000_attribute_table[] =
 #undef TARGET_VECTORIZE_DESTROY_COST_DATA
 #define TARGET_VECTORIZE_DESTROY_COST_DATA rs6000_destroy_cost_data
 
+#undef TARGET_LOOP_UNROLL_ADJUST
+#define TARGET_LOOP_UNROLL_ADJUST rs6000_loop_unroll_adjust
+
 #undef TARGET_INIT_BUILTINS
 #define TARGET_INIT_BUILTINS rs6000_init_builtins
 #undef TARGET_BUILTIN_DECL
@@ -4540,6 +4543,17 @@ rs6000_option_override_internal (bool global_init_p)
 			     global_options.x_param_values,
 			     global_options_set.x_param_values);
 
+      /* If funroll-loops is implicitly enabled, do not turn fweb or
+	 frename-registers on implicitly.  */
+      if (!global_options_set.x_flag_unroll_loops
+	  && !global_options_set.x_flag_unroll_all_loops)
+	{
+	  if (!global_options_set.x_flag_web)
+	    global_options.x_flag_web = 0;
+	  if (!global_options_set.x_flag_rename_registers)
+	    global_options.x_flag_rename_registers = 0;
+	}
+
       /* If using typedef char *va_list, signal that
 	 __builtin_va_start (&ap, 0) can be optimized to
 	 ap = __builtin_next_arg (0).  */
@@ -5081,6 +5095,29 @@ rs6000_destroy_cost_data (void *data)
   free (data);
 }
 
+/* This target hook implementation for TARGET_LOOP_UNROLL_ADJUST calculates
+   a new heristic number struct loop *loop should be unrolled.  */
+
+static unsigned
+rs6000_loop_unroll_adjust (unsigned nunroll, struct loop * loop)
+{
+  /* If funroll-loops was enabled implicitly, like at -O2, we only unroll
+     those small loops with small unroll factor.  */
+  if (!global_options_set.x_flag_unroll_loops
+      && !global_options_set.x_flag_unroll_all_loops)
+    {
+      /* If the loop contains few insns, treated it as small loops.
+	 TODO: Uing 10 hard code for now.  Continue to refine, For example,
+	 if loop constians only 1-2 insns, we may unroll more times(4).
+	 And we may use PARAM to control kinds of loop size.  */
+      if (loop->ninsns <= 10)
+	return 2;
+      else
+	return 0;
+    }
+  return nunroll;
+}
+
 /* Handler for the Mathematical Acceleration Subsystem (mass) interface to a
    library with vectorized intrinsics.  */
 
diff --git a/gcc/testsuite/c-c++-common/tsan/thread_leak2.c b/gcc/testsuite/c-c++-common/tsan/thread_leak2.c
index c9b8046..082f2aa 100644
--- a/gcc/testsuite/c-c++-common/tsan/thread_leak2.c
+++ b/gcc/testsuite/c-c++-common/tsan/thread_leak2.c
@@ -1,5 +1,9 @@
 /* { dg-shouldfail "tsan" } */
 
+/* { dg-additional-options "-fno-unroll-loops" { target { powerpc*-*-* } } } */
+/* -fno-unroll-loops help to avoid ThreadSanitizer reporting multi-times
+   message for pthread_create at difference calling addresses.  */
+
 #include <pthread.h>
 #include <unistd.h>
 
diff --git a/gcc/testsuite/gcc.target/powerpc/loop_align.c b/gcc/testsuite/gcc.target/powerpc/loop_align.c
index ebe3782..ef67f77 100644
--- a/gcc/testsuite/gcc.target/powerpc/loop_align.c
+++ b/gcc/testsuite/gcc.target/powerpc/loop_align.c
@@ -1,6 +1,6 @@
 /* { dg-do compile { target { powerpc*-*-* } } } */
 /* { dg-skip-if "" { powerpc*-*-darwin* powerpc-ibm-aix* } } */
-/* { dg-options "-O2 -mdejagnu-cpu=power7 -falign-functions=16" } */
+/* { dg-options "-O2 -mdejagnu-cpu=power7 -falign-functions=16 -fno-unroll-loops" } */
 /* { dg-final { scan-assembler ".p2align 5" } } */
 
 void f(double *a, double *b, double *c, unsigned long n) {
diff --git a/gcc/testsuite/gcc.target/powerpc/ppc-fma-1.c b/gcc/testsuite/gcc.target/powerpc/ppc-fma-1.c
index b4945e6..2a5b92c 100644
--- a/gcc/testsuite/gcc.target/powerpc/ppc-fma-1.c
+++ b/gcc/testsuite/gcc.target/powerpc/ppc-fma-1.c
@@ -1,7 +1,7 @@
 /* { dg-do compile { target { powerpc*-*-* } } } */
 /* { dg-skip-if "" { powerpc*-*-darwin* } } */
 /* { dg-require-effective-target powerpc_vsx_ok } */
-/* { dg-options "-O3 -ftree-vectorize -mdejagnu-cpu=power7 -ffast-math" } */
+/* { dg-options "-O3 -ftree-vectorize -mdejagnu-cpu=power7 -ffast-math -fno-unroll-loops" } */
 /* { dg-final { scan-assembler-times "xvmadd" 4 } } */
 /* { dg-final { scan-assembler-times "xsmadd\|fmadd\ " 2 } } */
 /* { dg-final { scan-assembler-times "fmadds" 2 } } */
diff --git a/gcc/testsuite/gcc.target/powerpc/ppc-fma-2.c b/gcc/testsuite/gcc.target/powerpc/ppc-fma-2.c
index 5ed630a..bf2c67f 100644
--- a/gcc/testsuite/gcc.target/powerpc/ppc-fma-2.c
+++ b/gcc/testsuite/gcc.target/powerpc/ppc-fma-2.c
@@ -1,7 +1,7 @@
 /* { dg-do compile { target { powerpc*-*-* } } } */
 /* { dg-skip-if "" { powerpc*-*-darwin* } } */
 /* { dg-require-effective-target powerpc_vsx_ok } */
-/* { dg-options "-O3 -ftree-vectorize -mdejagnu-cpu=power7 -ffast-math -ffp-contract=off" } */
+/* { dg-options "-O3 -ftree-vectorize -mdejagnu-cpu=power7 -ffast-math -ffp-contract=off -fno-unroll-loops" } */
 /* { dg-final { scan-assembler-times "xvmadd" 2 } } */
 /* { dg-final { scan-assembler-times "xsmadd\|fmadd\ " 1 } } */
 /* { dg-final { scan-assembler-times "fmadds" 1 } } */
diff --git a/gcc/testsuite/gcc.target/powerpc/ppc-fma-3.c b/gcc/testsuite/gcc.target/powerpc/ppc-fma-3.c
index ef252b3..8608116 100644
--- a/gcc/testsuite/gcc.target/powerpc/ppc-fma-3.c
+++ b/gcc/testsuite/gcc.target/powerpc/ppc-fma-3.c
@@ -2,7 +2,7 @@
 /* { dg-skip-if "" { powerpc*-*-darwin* } } */
 /* { dg-require-effective-target powerpc_altivec_ok } */
 /* { dg-require-effective-target powerpc_fprs } */
-/* { dg-options "-O3 -ftree-vectorize -mdejagnu-cpu=power6 -maltivec -ffast-math" } */
+/* { dg-options "-O3 -ftree-vectorize -mdejagnu-cpu=power6 -maltivec -ffast-math -fno-unroll-loops" } */
 /* { dg-final { scan-assembler-times "vmaddfp" 2 } } */
 /* { dg-final { scan-assembler-times "fmadd " 2 } } */
 /* { dg-final { scan-assembler-times "fmadds" 2 } } */
diff --git a/gcc/testsuite/gcc.target/powerpc/ppc-fma-4.c b/gcc/testsuite/gcc.target/powerpc/ppc-fma-4.c
index c2eaf1a..291c2ee 100644
--- a/gcc/testsuite/gcc.target/powerpc/ppc-fma-4.c
+++ b/gcc/testsuite/gcc.target/powerpc/ppc-fma-4.c
@@ -2,7 +2,7 @@
 /* { dg-skip-if "" { powerpc*-*-darwin* } } */
 /* { dg-require-effective-target powerpc_altivec_ok } */
 /* { dg-require-effective-target powerpc_fprs } */
-/* { dg-options "-O3 -ftree-vectorize -mdejagnu-cpu=power6 -maltivec -ffast-math -ffp-contract=off" } */
+/* { dg-options "-O3 -ftree-vectorize -mdejagnu-cpu=power6 -maltivec -ffast-math -ffp-contract=off -fno-unroll-loops" } */
 /* { dg-final { scan-assembler-times "vmaddfp" 1 } } */
 /* { dg-final { scan-assembler-times "fmadd " 1 } } */
 /* { dg-final { scan-assembler-times "fmadds" 1 } } */
diff --git a/gcc/testsuite/gcc.target/powerpc/pr78604.c b/gcc/testsuite/gcc.target/powerpc/pr78604.c
index 76d8945..35bfdb3 100644
--- a/gcc/testsuite/gcc.target/powerpc/pr78604.c
+++ b/gcc/testsuite/gcc.target/powerpc/pr78604.c
@@ -1,7 +1,7 @@
 /* { dg-do compile { target { powerpc*-*-* } } } */
 /* { dg-skip-if "" { powerpc*-*-darwin* } } */
 /* { dg-require-effective-target powerpc_p8vector_ok } */
-/* { dg-options "-mdejagnu-cpu=power8 -O2 -ftree-vectorize -fdump-tree-vect-details" } */
+/* { dg-options "-mdejagnu-cpu=power8 -O2 -ftree-vectorize -fdump-tree-vect-details -fno-unroll-loops" } */
 
 #ifndef SIZE
 #define SIZE 1024
diff --git a/gcc/testsuite/gcc.target/powerpc/small-loop-unroll.c b/gcc/testsuite/gcc.target/powerpc/small-loop-unroll.c
new file mode 100644
index 0000000..fec5ae9
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/small-loop-unroll.c
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-rtl-loop2_unroll" } */
+
+void __attribute__ ((noinline)) foo(int n, int *arr)
+{
+  int i;
+  for (i = 0; i < n; i++)
+    arr[i] = arr[i] - 10;
+}
+/* { dg-final { scan-rtl-dump-times "Unrolled loop 1 times" 1 "loop2_unroll" } } */
+/* { dg-final { scan-assembler-times {\mlwz\M} 3 } } */
+/* { dg-final { scan-assembler-times {\mstw\M} 3 } } */
+
