[PATCH V4] rs6000: cannot_force_const_mem for HIGH code rtx[PR106460]

[PATCH V4] rs6000: cannot_force_const_mem for HIGH code rtx[PR106460]

[Jiufu Guo]

Hi,

As the issue in PR106460, a rtx 'high:DI (symbol_ref:DI ("var_48")' is tried
to store into constant pool and ICE occur.  But actually, this rtx represents
partial incomplete address and can not be put into a .rodata section.

This patch updates rs6000_cannot_force_const_mem to return true for rtx(s) with
HIGH code, because these rtx(s) indicate part of address and are not ok for
constant pool.

Below are some examples:
(high:DI (const:DI (plus:DI (symbol_ref:DI ("xx") (const_int 12 [0xc])))))
(high:DI (symbol_ref:DI ("var_1")..)))

This patch updated the patchV3 according previous comments.
https://gcc.gnu.org/pipermail/gcc-patches/2022-September/602308.html

Bootstrap and regtest pass on ppc64 and ppc64le.
Is this ok for trunk.

BR,
Jeff(Jiufu)

	PR target/106460

gcc/ChangeLog:

	* config/rs6000/rs6000.cc (rs6000_cannot_force_const_mem): Return true
	for HIGH code rtx.

gcc/testsuite/ChangeLog:

	* gcc.target/powerpc/pr106460.c: New test.

---
 gcc/config/rs6000/rs6000.cc                 |  7 +++++--
 gcc/testsuite/gcc.target/powerpc/pr106460.c | 12 ++++++++++++
 2 files changed, 17 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/powerpc/pr106460.c

diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 5f347e9574f..dab66f9213a 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -9759,8 +9759,11 @@ rs6000_init_stack_protect_guard (void)
 static bool
 rs6000_cannot_force_const_mem (machine_mode mode ATTRIBUTE_UNUSED, rtx x)
 {
-  if (GET_CODE (x) == HIGH
-      && GET_CODE (XEXP (x, 0)) == UNSPEC)
+  /* If GET_CODE (x) is HIGH, the 'X' represets the high part of a symbol_ref.
+     It can not be put into a constant pool.  e.g.
+     (high:DI (unspec:DI [(symbol_ref/u:DI ("*.LC0")..)
+     (high:DI (symbol_ref:DI ("var")..)).  */
+  if (GET_CODE (x) == HIGH)
     return true;
 
   /* A TLS symbol in the TOC cannot contain a sum.  */
diff --git a/gcc/testsuite/gcc.target/powerpc/pr106460.c b/gcc/testsuite/gcc.target/powerpc/pr106460.c
new file mode 100644
index 00000000000..aae4b015bba
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr106460.c
@@ -0,0 +1,12 @@
+/* { dg-require-effective-target power10_ok } */
+/* { dg-options "-O1 -mdejagnu-cpu=power10" } */
+
+/* (high:DI (symbol_ref:DI ("var_48")..))) should not cause ICE. */
+extern short var_48;
+void
+foo (double *r)
+{
+  if (var_48)
+    *r = 1234.5678;
+}
+
-- 
2.17.1

Re: [PATCH V4] rs6000: cannot_force_const_mem for HIGH code rtx[PR106460]

[Kewen.Lin]

Hi Jeff,

on 2022/10/12 14:48, Jiufu Guo via Gcc-patches wrote:
> Hi,
> 
> As the issue in PR106460, a rtx 'high:DI (symbol_ref:DI ("var_48")' is tried
> to store into constant pool and ICE occur.  But actually, this rtx represents
> partial incomplete address and can not be put into a .rodata section.
> 
> This patch updates rs6000_cannot_force_const_mem to return true for rtx(s) with
> HIGH code, because these rtx(s) indicate part of address and are not ok for
> constant pool.
> 
> Below are some examples:
> (high:DI (const:DI (plus:DI (symbol_ref:DI ("xx") (const_int 12 [0xc])))))
> (high:DI (symbol_ref:DI ("var_1")..)))
> 
> This patch updated the patchV3 according previous comments.
> https://gcc.gnu.org/pipermail/gcc-patches/2022-September/602308.html
> 
> Bootstrap and regtest pass on ppc64 and ppc64le.
> Is this ok for trunk.

This patch is ok, thanks!

BR,
Kewen

> 
> BR,
> Jeff(Jiufu)
> 
> 	PR target/106460
> 
> gcc/ChangeLog:
> 
> 	* config/rs6000/rs6000.cc (rs6000_cannot_force_const_mem): Return true
> 	for HIGH code rtx.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* gcc.target/powerpc/pr106460.c: New test.
> 
> ---
>  gcc/config/rs6000/rs6000.cc                 |  7 +++++--
>  gcc/testsuite/gcc.target/powerpc/pr106460.c | 12 ++++++++++++
>  2 files changed, 17 insertions(+), 2 deletions(-)
>  create mode 100644 gcc/testsuite/gcc.target/powerpc/pr106460.c
> 
> diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
> index 5f347e9574f..dab66f9213a 100644
> --- a/gcc/config/rs6000/rs6000.cc
> +++ b/gcc/config/rs6000/rs6000.cc
> @@ -9759,8 +9759,11 @@ rs6000_init_stack_protect_guard (void)
>  static bool
>  rs6000_cannot_force_const_mem (machine_mode mode ATTRIBUTE_UNUSED, rtx x)
>  {
> -  if (GET_CODE (x) == HIGH
> -      && GET_CODE (XEXP (x, 0)) == UNSPEC)
> +  /* If GET_CODE (x) is HIGH, the 'X' represets the high part of a symbol_ref.
> +     It can not be put into a constant pool.  e.g.
> +     (high:DI (unspec:DI [(symbol_ref/u:DI ("*.LC0")..)
> +     (high:DI (symbol_ref:DI ("var")..)).  */
> +  if (GET_CODE (x) == HIGH)
>      return true;
>  
>    /* A TLS symbol in the TOC cannot contain a sum.  */
> diff --git a/gcc/testsuite/gcc.target/powerpc/pr106460.c b/gcc/testsuite/gcc.target/powerpc/pr106460.c
> new file mode 100644
> index 00000000000..aae4b015bba
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pr106460.c
> @@ -0,0 +1,12 @@
> +/* { dg-require-effective-target power10_ok } */
> +/* { dg-options "-O1 -mdejagnu-cpu=power10" } */
> +
> +/* (high:DI (symbol_ref:DI ("var_48")..))) should not cause ICE. */
> +extern short var_48;
> +void
> +foo (double *r)
> +{
> +  if (var_48)
> +    *r = 1234.5678;
> +}
> +