diff mbox

[AARCH64] improve float/double 0.0 support

Message ID CABXYE2U4vrpooOSVgB1K_WBKQnSJ6mZRwBxm_q9YtASafxSoMg@mail.gmail.com
State New
Headers show

Commit Message

Jim Wilson June 19, 2015, 4:43 p.m. UTC
This is a follow on to the long double 0.0 patch.  The float and
double support has similar problems and need similar fixes, though a
little smaller in scope.  Before the patch this testcase
void sub1 (float *f)  { *f = 0.0; }
void sub2 (double *d) { *d = 0.0; }
gives assembly code
sub1:
        fmov    s0, wzr
        str     s0, [x0]
...
sub2:
        fmov    d0, xzr
        str     d0, [x0]
after the patch, the assembly code is
sub1:
        str     wzr, [x0]
...
sub2:
        str     xzr, [x0]

The fixes are along the same lines as the earlier long double patch.
The expander is changed so that a zero source isn't forced into a reg,
the patterns are changed to allow a zero source, and the instruction
types are changed because storing zero to mem is an integer
instruction not an FP instruction.

Testing showed that we have testcases for float/double 0, but the
testcases are a little confused as they are storing 0 to mem and
expecting to see an fmov instruction.  I split the testcases into two,
so we can have a  0 to reg case that expects fmov, and a 0 to mem case
that expects str of the zero reg.  I also added the equivalent missing
long double testcases.

This was tested with a default languages make bootstrap and make
check..  I see an additional 8 passes, and no other change in the
testsuite results.

Jim
diff mbox

Patch

gcc/
2015-06-19  Jim Wilson  <jim.wilson@linaro.org>

	* config/aarch64/aarch64.md (mov<mode>:GPF): Don't call force_reg if
	op1 is an fp zero.
	(movsf_aarch64): Change condition from register_operand to
	aarch64_reg_or_fp_zero for op1.  Change type for alternative 6 to
	load1.  Change type for alternative 7 to store1.
	(movdf_aarch64): Likewise.

gcc/testsuite/
2015-06-19  Jim Wilson  <jim.wilson@linaro.org>

	* gcc.target/aarch64/fmovd-zero-mem.c: New.
	* gcc.target/aarch64/fmovd-zero-reg.c: New.
	* gcc.target/aarch64/fmovf-zero-mem.c: New.
	* gcc.target/aarch64/fmovf-zero-reg.c: New.
	* gcc.target/aarch64/fmovld-zero-mem.c: New.
	* gcc.target/aarch64/fmovld-zero-mem.c: New.
	* gcc.target/aarch64/fmovd-zero.c: Delete.
	* gcc.target/aarch64/fmovf-zero.c: Delete.

Index: config/aarch64/aarch64.md
===================================================================
--- config/aarch64/aarch64.md	(revision 224493)
+++ config/aarch64/aarch64.md	(working copy)
@@ -986,7 +986,9 @@  (define_expand "mov<mode>"
 	FAIL;
      }
 
-    if (GET_CODE (operands[0]) == MEM)
+    if (GET_CODE (operands[0]) == MEM
+        && ! (GET_CODE (operands[1]) == CONST_DOUBLE
+	      && aarch64_float_const_zero_rtx_p (operands[1])))
       operands[1] = force_reg (<MODE>mode, operands[1]);
   "
 )
@@ -995,7 +997,7 @@  (define_insn "*movsf_aarch64"
   [(set (match_operand:SF 0 "nonimmediate_operand" "=w, ?r,w,w  ,w,m,r,m ,r")
 	(match_operand:SF 1 "general_operand"      "?rY, w,w,Ufc,m,w,m,rY,r"))]
   "TARGET_FLOAT && (register_operand (operands[0], SFmode)
-    || register_operand (operands[1], SFmode))"
+    || aarch64_reg_or_fp_zero (operands[1], SFmode))"
   "@
    fmov\\t%s0, %w1
    fmov\\t%w0, %s1
@@ -1007,14 +1009,14 @@  (define_insn "*movsf_aarch64"
    str\\t%w1, %0
    mov\\t%w0, %w1"
   [(set_attr "type" "f_mcr,f_mrc,fmov,fconsts,\
-                     f_loads,f_stores,f_loads,f_stores,mov_reg")]
+                     f_loads,f_stores,load1,store1,mov_reg")]
 )
 
 (define_insn "*movdf_aarch64"
   [(set (match_operand:DF 0 "nonimmediate_operand" "=w, ?r,w,w  ,w,m,r,m ,r")
 	(match_operand:DF 1 "general_operand"      "?rY, w,w,Ufc,m,w,m,rY,r"))]
   "TARGET_FLOAT && (register_operand (operands[0], DFmode)
-    || register_operand (operands[1], DFmode))"
+    || aarch64_reg_or_fp_zero (operands[1], DFmode))"
   "@
    fmov\\t%d0, %x1
    fmov\\t%x0, %d1
@@ -1026,7 +1028,7 @@  (define_insn "*movdf_aarch64"
    str\\t%x1, %0
    mov\\t%x0, %x1"
   [(set_attr "type" "f_mcr,f_mrc,fmov,fconstd,\
-                     f_loadd,f_stored,f_loadd,f_stored,mov_reg")]
+                     f_loadd,f_stored,load1,store1,mov_reg")]
 )
 
 (define_expand "movtf"
Index: testsuite/gcc.target/aarch64/fmovd-zero-mem.c
===================================================================
--- testsuite/gcc.target/aarch64/fmovd-zero-mem.c	(revision 0)
+++ testsuite/gcc.target/aarch64/fmovd-zero-mem.c	(working copy)
@@ -0,0 +1,10 @@ 
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+void
+foo (double *output)
+{
+  *output = 0.0;
+}
+
+/* { dg-final { scan-assembler "str\\txzr, \\\[x0\\\]" } } */
Index: testsuite/gcc.target/aarch64/fmovd-zero-reg.c
===================================================================
--- testsuite/gcc.target/aarch64/fmovd-zero-reg.c	(revision 0)
+++ testsuite/gcc.target/aarch64/fmovd-zero-reg.c	(working copy)
@@ -0,0 +1,11 @@ 
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+void bar (double);
+void
+foo (void)
+{
+  bar (0.0);
+}
+
+/* { dg-final { scan-assembler "fmov\\td0, xzr" } } */
Index: testsuite/gcc.target/aarch64/fmovd-zero.c
===================================================================
--- testsuite/gcc.target/aarch64/fmovd-zero.c	(revision 224493)
+++ testsuite/gcc.target/aarch64/fmovd-zero.c	(working copy)
@@ -1,10 +0,0 @@ 
-/* { dg-do compile } */
-/* { dg-options "-O2" } */
-
-void
-foo (double *output)
-{
-  *output = 0.0;
-}
-
-/* { dg-final { scan-assembler "fmov\\td\[0-9\]+, xzr" } } */
Index: testsuite/gcc.target/aarch64/fmovf-zero-mem.c
===================================================================
--- testsuite/gcc.target/aarch64/fmovf-zero-mem.c	(revision 0)
+++ testsuite/gcc.target/aarch64/fmovf-zero-mem.c	(working copy)
@@ -0,0 +1,10 @@ 
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+void
+foo (float *output)
+{
+  *output = 0.0;
+}
+
+/* { dg-final { scan-assembler "str\\twzr, \\\[x0\\\]" } } */
Index: testsuite/gcc.target/aarch64/fmovf-zero-reg.c
===================================================================
--- testsuite/gcc.target/aarch64/fmovf-zero-reg.c	(revision 0)
+++ testsuite/gcc.target/aarch64/fmovf-zero-reg.c	(working copy)
@@ -0,0 +1,11 @@ 
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+void bar (float);
+void
+foo (void)
+{
+  bar (0.0);
+}
+
+/* { dg-final { scan-assembler "fmov\\ts0, wzr" } } */
Index: testsuite/gcc.target/aarch64/fmovf-zero.c
===================================================================
--- testsuite/gcc.target/aarch64/fmovf-zero.c	(revision 224493)
+++ testsuite/gcc.target/aarch64/fmovf-zero.c	(working copy)
@@ -1,10 +0,0 @@ 
-/* { dg-do compile } */
-/* { dg-options "-O2" } */
-
-void
-foo (float *output)
-{
-  *output = 0.0;
-}
-
-/* { dg-final { scan-assembler "fmov\\ts\[0-9\]+, wzr" } } */
Index: testsuite/gcc.target/aarch64/fmovld-zero-mem.c
===================================================================
--- testsuite/gcc.target/aarch64/fmovld-zero-mem.c	(revision 0)
+++ testsuite/gcc.target/aarch64/fmovld-zero-mem.c	(working copy)
@@ -0,0 +1,10 @@ 
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+void
+foo (long double *output)
+{
+  *output = 0.0;
+}
+
+/* { dg-final { scan-assembler "stp\\txzr, xzr, \\\[x0\\\]" } } */
Index: testsuite/gcc.target/aarch64/fmovld-zero-reg.c
===================================================================
--- testsuite/gcc.target/aarch64/fmovld-zero-reg.c	(revision 0)
+++ testsuite/gcc.target/aarch64/fmovld-zero-reg.c	(working copy)
@@ -0,0 +1,11 @@ 
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+void bar (long double);
+void
+foo (void)
+{
+  bar (0.0);
+}
+
+/* { dg-final { scan-assembler "movi\\tv0\.2d, #0" } } */