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[GCC/ARM/gcc-6-branch] Backport PR71607

Message ID 20170602112338.62hz2jqefaby6pzl@e107464-lin.cambridge.arm.com
State New
Headers show

Commit Message

Prakhar Bahuguna June 2, 2017, 11:23 a.m. UTC 
This patch tackles the issue reported in PR71607. This patch takes a different
approach for disabling the creation of literal pools. Instead of disabling the
patterns that would normally transform the rtl into actual literal pools, it
disables the creation of this literal pool rtl by making the target hook
TARGET_CANNOT_FORCE_CONST_MEM return true if arm_disable_literal_pool is true.
I added patterns to split floating point constants for both SF and DFmode. A
pattern to handle the addressing of label_refs had to be included as well since
all "memory_operand" patterns are disabled when TARGET_CANNOT_FORCE_CONST_MEM
returns true. Also the pattern for splitting 32-bit immediates had to be
changed, it was not accepting unsigned 32-bit unsigned integers with the MSB
set. I believe const_int_operand expects the mode of the operand to be set to
VOIDmode and not SImode. I have only changed it in the patterns that were
affecting this code, though I suggest looking into changing it in the rest of
the ARM backend.

Additionally, the use of thread-local storage is disabled if literal pools are
disabled, as there are no relocations for TLS variables and incorrect code is
generated as a result. The patch now emits a diagnostic in TLS-enabled
toolchains if a TLS symbol is found when -mpure-code or -mslow-flash-data are
enabled.

2017-06-02  Prakhar Bahuguna  <prakhar.bahuguna@arm.com>

	Backport from mainline
	2017-05-05  Andre Vieira  <andre.simoesdiasvieira@arm.com>
		    Prakhar Bahuguna  <prakhar.bahuguna@arm.com>

	gcc/
	PR target/71607
	* config/arm/arm.md (use_literal_pool): Remove.
	(64-bit immediate split): No longer takes cost into consideration
	if arm_disable_literal_pool is enabled.
	* config/arm/arm.c (arm_tls_referenced_p): Add diagnostic if TLS is
	used when arm_disable_literal_pool is enabled.
	(arm_max_const_double_inline_cost): Remove use of
	arm_disable_literal_pool.
	(push_minipool_fix): Add assert.
	(arm_reorg): Add return if arm_disable_literal_pool is enabled.
	* config/arm/vfp.md (no_literal_pool_df_immediate): New.
	(no_literal_pool_sf_immediate): New.

	2017-05-05  Andre Vieira  <andre.simoesdiasvieira@arm.com>
		    Thomas Preud'homme  <thomas.preudhomme@arm.com>
		    Prakhar Bahuguna  <prakhar.bahuguna@arm.com>

	gcc/testsuite/
	PR target/71607
	* gcc.target/arm/thumb2-slow-flash-data.c: Renamed to ...
	* gcc.target/arm/thumb2-slow-flash-data-1.c: ... this.
	* gcc.target/arm/thumb2-slow-flash-data-2.c: New.
	* gcc.target/arm/thumb2-slow-flash-data-3.c: New.
	* gcc.target/arm/thumb2-slow-flash-data-4.c: New.
	* gcc.target/arm/thumb2-slow-flash-data-5.c: New.
	* gcc.target/arm/tls-disable-literal-pool.c: New.

Testing done: Ran regression tests for arm-eabi-none for ARMv7-M and ARMv8-M
targets. A bootstrap for arm-none-linux-gnueabihf was also successful.

Okay for 6 branch?
diff mbox

Patch

diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 9c0813d598d..7fa8275550a 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -8240,7 +8240,16 @@  arm_tls_referenced_p (rtx x)
     {
       const_rtx x = *iter;
       if (GET_CODE (x) == SYMBOL_REF && SYMBOL_REF_TLS_MODEL (x) != 0)
-	return true;
+	{
+	  /* ARM currently does not provide relocations to encode TLS variables
+	     into AArch32 instructions, only data, so there is no way to
+	     currently implement these if a literal pool is disabled.  */
+	  if (arm_disable_literal_pool)
+	    sorry ("accessing thread-local storage is not currently supported "
+		   "with -mpure-code or -mslow-flash-data");
+
+	  return true;
+	}
 
       /* Don't recurse into UNSPEC_TLS looking for TLS symbols; these are
 	 TLS offsets, not real symbol references.  */
@@ -17087,6 +17096,7 @@  static void
 push_minipool_fix (rtx_insn *insn, HOST_WIDE_INT address, rtx *loc,
 		   machine_mode mode, rtx value)
 {
+  gcc_assert (!arm_disable_literal_pool);
   Mfix * fix = (Mfix *) obstack_alloc (&minipool_obstack, sizeof (* fix));
 
   fix->insn = insn;
@@ -17138,10 +17148,6 @@  push_minipool_fix (rtx_insn *insn, HOST_WIDE_INT address, rtx *loc,
 int
 arm_max_const_double_inline_cost ()
 {
-  /* Let the value get synthesized to avoid the use of literal pools.  */
-  if (arm_disable_literal_pool)
-    return 99;
-
   return ((optimize_size || arm_ld_sched) ? 3 : 4);
 }
 
@@ -17622,6 +17628,11 @@  arm_reorg (void)
   if (!optimize)
     split_all_insns_noflow ();
 
+  /* Make sure we do not attempt to create a literal pool even though it should
+     no longer be necessary to create any.  */
+  if (arm_disable_literal_pool)
+    return ;
+
   minipool_fix_head = minipool_fix_tail = NULL;
 
   /* The first insn must always be a note, or the code below won't
diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
index 86df1c0366b..19f0ddb4e51 100644
--- a/gcc/config/arm/arm.md
+++ b/gcc/config/arm/arm.md
@@ -225,10 +225,6 @@ 
 	       (match_test "arm_restrict_it"))
 	  (const_string "no")
 
-	  (and (eq_attr "use_literal_pool" "yes")
-	       (match_test "arm_disable_literal_pool"))
-	  (const_string "no")
-
 	  (eq_attr "arch_enabled" "no")
 	  (const_string "no")]
 	 (const_string "yes")))
@@ -5518,8 +5514,9 @@ 
 	(match_operand:ANY64 1 "immediate_operand" ""))]
   "TARGET_32BIT
    && reload_completed
-   && (arm_const_double_inline_cost (operands[1])
-       <= arm_max_const_double_inline_cost ())"
+   && (arm_disable_literal_pool
+       || (arm_const_double_inline_cost (operands[1])
+	   <= arm_max_const_double_inline_cost ()))"
   [(const_int 0)]
   "
   arm_split_constant (SET, SImode, curr_insn,
diff --git a/gcc/config/arm/vfp.md b/gcc/config/arm/vfp.md
index ac5f3b862b5..54020aa08a1 100644
--- a/gcc/config/arm/vfp.md
+++ b/gcc/config/arm/vfp.md
@@ -1401,3 +1401,40 @@ 
 ;; fmdhr et al (VFPv1)
 ;; Support for xD (single precision only) variants.
 ;; fmrrs, fmsrr
+
+;; Split an immediate DF move to two immediate SI moves.
+(define_insn_and_split "no_literal_pool_df_immediate"
+  [(set (match_operand:DF 0 "s_register_operand" "")
+	(match_operand:DF 1 "const_double_operand" ""))]
+  "TARGET_THUMB2 && arm_disable_literal_pool
+  && !(TARGET_HARD_FLOAT && TARGET_VFP_DOUBLE
+       && vfp3_const_double_rtx (operands[1]))"
+  "#"
+  "&& !reload_completed"
+  [(set (subreg:SI (match_dup 1) 0) (match_dup 2))
+   (set (subreg:SI (match_dup 1) 4) (match_dup 3))
+   (set (match_dup 0) (match_dup 1))]
+  "
+  long buf[2];
+  real_to_target (buf, CONST_DOUBLE_REAL_VALUE (operands[1]), DFmode);
+  operands[2] = GEN_INT ((int) buf[0]);
+  operands[3] = GEN_INT ((int) buf[1]);
+  operands[1] = gen_reg_rtx (DFmode);
+  ")
+
+;; Split an immediate SF move to one immediate SI move.
+(define_insn_and_split "no_literal_pool_sf_immediate"
+  [(set (match_operand:SF 0 "s_register_operand" "")
+	(match_operand:SF 1 "const_double_operand" ""))]
+  "TARGET_THUMB2 && arm_disable_literal_pool
+  && !(TARGET_HARD_FLOAT && vfp3_const_double_rtx (operands[1]))"
+  "#"
+  "&& !reload_completed"
+  [(set (subreg:SI (match_dup 1) 0) (match_dup 2))
+   (set (match_dup 0) (match_dup 1))]
+  "
+  long buf;
+  real_to_target (&buf, CONST_DOUBLE_REAL_VALUE (operands[1]), SFmode);
+  operands[2] = GEN_INT ((int) buf);
+  operands[1] = gen_reg_rtx (SFmode);
+  ")
diff --git a/gcc/testsuite/gcc.target/arm/thumb2-slow-flash-data.c b/gcc/testsuite/gcc.target/arm/thumb2-slow-flash-data-1.c
similarity index 100%
rename from gcc/testsuite/gcc.target/arm/thumb2-slow-flash-data.c
rename to gcc/testsuite/gcc.target/arm/thumb2-slow-flash-data-1.c
diff --git a/gcc/testsuite/gcc.target/arm/thumb2-slow-flash-data-2.c b/gcc/testsuite/gcc.target/arm/thumb2-slow-flash-data-2.c
new file mode 100644
index 00000000000..6e76043daee
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/thumb2-slow-flash-data-2.c
@@ -0,0 +1,28 @@ 
+/* { dg-do compile } */
+/* { dg-require-effective-target arm_cortex_m } */
+/* { dg-require-effective-target arm_thumb2_ok } */
+/* { dg-skip-if "avoid conflicts with multilib options" { *-*-* } { "-mcpu=*" } { "-mcpu=cortex-m4" "-mcpu=cortex-m7" } } */
+/* { dg-skip-if "do not override -mfloat-abi" { *-*-* } { "-mfloat-abi=*" } { "-mfloat-abi=hard" } } */
+/* { dg-options "-march=armv7e-m -mfloat-abi=hard -O2 -mthumb -mslow-flash-data" } */
+
+float f (float);
+
+const float max = 0.01f;
+
+int
+g (float in)
+{
+  if (f (in) + f (in) < max)
+    return 0;
+  return 1;
+}
+
+double foo (void)
+{
+  return 0xF1EC7A5239123AF;
+}
+
+double bar (void)
+{
+  return 0.0f;
+}
diff --git a/gcc/testsuite/gcc.target/arm/thumb2-slow-flash-data-3.c b/gcc/testsuite/gcc.target/arm/thumb2-slow-flash-data-3.c
new file mode 100644
index 00000000000..fe7a12bf99b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/thumb2-slow-flash-data-3.c
@@ -0,0 +1,25 @@ 
+/* { dg-do compile } */
+/* { dg-require-effective-target arm_cortex_m } */
+/* { dg-require-effective-target arm_thumb2_ok } */
+/* { dg-skip-if "avoid conflicts with multilib options" { *-*-* } { "-mcpu=*" } { "-mcpu=cortex-m4" "-mcpu=cortex-m7" } } */
+/* { dg-skip-if "do not override -mfloat-abi" { *-*-* } { "-mfloat-abi=*" } { "-mfloat-abi=hard" } } */
+/* { dg-options "-march=armv7e-m -mfloat-abi=hard -mthumb -mslow-flash-data" } */
+
+/* From PR71607 */
+
+float b;
+void fn1 ();
+
+float
+fn2 ()
+{
+  return 1.1f;
+}
+
+void
+fn3 ()
+{
+  float a[2];
+  a[1] = b;
+  fn1 (a);
+}
diff --git a/gcc/testsuite/gcc.target/arm/thumb2-slow-flash-data-4.c b/gcc/testsuite/gcc.target/arm/thumb2-slow-flash-data-4.c
new file mode 100644
index 00000000000..cc5aea4437f
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/thumb2-slow-flash-data-4.c
@@ -0,0 +1,26 @@ 
+/* { dg-do compile } */
+/* { dg-require-effective-target arm_cortex_m } */
+/* { dg-require-effective-target arm_thumb2_ok } */
+/* { dg-skip-if "avoid conflicts with multilib options" { *-*-* } { "-mcpu=*" } { "-mcpu=cortex-m4" "-mcpu=cortex-m7" } } */
+/* { dg-skip-if "do not override -mfloat-abi" { *-*-* } { "-mfloat-abi=*" } { "-mfloat-abi=hard" } } */
+/* { dg-options "-march=armv7e-m -mfloat-abi=hard -O2 -mthumb -mslow-flash-data" } */
+
+double __attribute__ ((target ("fpu=fpv5-d16")))
+foo (void)
+{
+  return 1.0f;
+}
+
+float __attribute__ ((target ("fpu=fpv5-d16")))
+bar (void)
+{
+  return 1.0f;
+}
+
+float __attribute__ ((target ("fpu=fpv5-sp-d16")))
+baz (void)
+{
+  return 1.0f;
+}
+
+/* { dg-final { scan-assembler-times "#1\\.0e\\+0" 3 } } */
diff --git a/gcc/testsuite/gcc.target/arm/thumb2-slow-flash-data-5.c b/gcc/testsuite/gcc.target/arm/thumb2-slow-flash-data-5.c
new file mode 100644
index 00000000000..b9161c4a4b4
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/thumb2-slow-flash-data-5.c
@@ -0,0 +1,14 @@ 
+/* { dg-do compile } */
+/* { dg-require-effective-target arm_cortex_m } */
+/* { dg-require-effective-target arm_thumb2_ok } */
+/* { dg-skip-if "avoid conflicts with multilib options" { *-*-* } { "-mcpu=*" } { "-mcpu=cortex-m4" "-mcpu=cortex-m7" } } */
+/* { dg-skip-if "do not override -mfloat-abi" { *-*-* } { "-mfloat-abi=*" } { "-mfloat-abi=hard" } } */
+/* { dg-options "-march=armv7e-m -mfloat-abi=hard -O2 -mthumb -mslow-flash-data" } */
+
+double __attribute__ ((target ("fpu=fpv5-sp-d16")))
+foo (void)
+{
+  return 1.0f;
+}
+
+/* { dg-final { scan-assembler-not "#1\\.0e\\+0" } } */
diff --git a/gcc/testsuite/gcc.target/arm/tls-disable-literal-pool.c b/gcc/testsuite/gcc.target/arm/tls-disable-literal-pool.c
new file mode 100644
index 00000000000..283201fdd97
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/tls-disable-literal-pool.c
@@ -0,0 +1,14 @@ 
+/* { dg-do compile } */
+/* { dg-require-effective-target tls_native } */
+/* { dg-require-effective-target arm_cortex_m } */
+/* { dg-require-effective-target arm_thumb2_ok } */
+/* { dg-options "-mslow-flash-data" } */
+
+__thread int x = 0;
+
+int
+bar ()
+{
+  return x; /* { dg-message "sorry, unimplemented: accessing thread-local storage is not currently supported with -mpure-code or -mslow-flash-data" } */
+}
+