[gcc r12-9688] Darwin, PPC: Fix struct layout with pragma pack [PR110044].

[gcc r12-9688] Darwin, PPC: Fix struct layout with pragma pack [PR110044].

[Iain D Sandoe]

https://gcc.gnu.org/g:8d64b55db0bec62873503739fabc2a4d3219ad58

commit r12-9688-g8d64b55db0bec62873503739fabc2a4d3219ad58
Author: Iain Sandoe <iain@sandoe.co.uk>
Date:   Thu Jun 1 13:43:35 2023 +0100

    Darwin, PPC: Fix struct layout with pragma pack [PR110044].
    
    This bug was essentially that darwin_rs6000_special_round_type_align()
    was ignoring externally-imposed capping of field alignment.
    
    Signed-off-by: Iain Sandoe <iain@sandoe.co.uk>
    
            PR target/110044
    
    gcc/ChangeLog:
    
            * config/rs6000/rs6000.cc (darwin_rs6000_special_round_type_align):
            Make sure that we do not have a cap on field alignment before altering
            the struct layout based on the type alignment of the first entry.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.target/powerpc/darwin-abi-13-0.c: New test.
            * gcc.target/powerpc/darwin-abi-13-1.c: New test.
            * gcc.target/powerpc/darwin-abi-13-2.c: New test.
            * gcc.target/powerpc/darwin-structs-0.h: New test.
    
    (cherry picked from commit 84d080a29a780973bef47171ba708ae2f7b4ee47)

Diff:
---
 gcc/config/rs6000/rs6000.cc                        |  3 ++-
 gcc/testsuite/gcc.target/powerpc/darwin-abi-13-0.c | 23 +++++++++++++++++
 gcc/testsuite/gcc.target/powerpc/darwin-abi-13-1.c | 27 ++++++++++++++++++++
 gcc/testsuite/gcc.target/powerpc/darwin-abi-13-2.c | 27 ++++++++++++++++++++
 .../gcc.target/powerpc/darwin-structs-0.h          | 29 ++++++++++++++++++++++
 5 files changed, 108 insertions(+), 1 deletion(-)

diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index f678561071a..56941e6e2df 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -8128,7 +8128,8 @@ darwin_rs6000_special_round_type_align (tree type, unsigned int computed,
       type = TREE_TYPE (type);
   } while (AGGREGATE_TYPE_P (type));
 
-  if (! AGGREGATE_TYPE_P (type) && type != error_mark_node)
+  if (type != error_mark_node && ! AGGREGATE_TYPE_P (type)
+      && ! TYPE_PACKED (type) && maximum_field_alignment == 0)
     align = MAX (align, TYPE_ALIGN (type));
 
   return align;
diff --git a/gcc/testsuite/gcc.target/powerpc/darwin-abi-13-0.c b/gcc/testsuite/gcc.target/powerpc/darwin-abi-13-0.c
new file mode 100644
index 00000000000..d8d3c63a083
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/darwin-abi-13-0.c
@@ -0,0 +1,23 @@
+/* { dg-do compile { target powerpc*-*-darwin* } } */
+/* { dg-require-effective-target ilp32 } */
+/* { dg-options "-Wno-long-long" } */
+
+#include "darwin-structs-0.h"
+
+int tcd[sizeof(cd) != 12 ? -1 : 1];
+int acd[__alignof__(cd) != 4 ? -1 : 1];
+
+int sdc[sizeof(dc) != 16 ? -1 : 1];
+int adc[__alignof__(dc) != 8 ? -1 : 1];
+
+int scL[sizeof(cL) != 12 ? -1 : 1];
+int acL[__alignof__(cL) != 4 ? -1 : 1];
+
+int sLc[sizeof(Lc) != 16 ? -1 : 1];
+int aLc[__alignof__(Lc) != 8 ? -1 : 1];
+
+int scD[sizeof(cD) != 32 ? -1 : 1];
+int acD[__alignof__(cD) != 16 ? -1 : 1];
+
+int sDc[sizeof(Dc) != 32 ? -1 : 1];
+int aDc[__alignof__(Dc) != 16 ? -1 : 1];
diff --git a/gcc/testsuite/gcc.target/powerpc/darwin-abi-13-1.c b/gcc/testsuite/gcc.target/powerpc/darwin-abi-13-1.c
new file mode 100644
index 00000000000..4d888d383fa
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/darwin-abi-13-1.c
@@ -0,0 +1,27 @@
+/* { dg-do compile { target powerpc*-*-darwin* } } */
+/* { dg-require-effective-target ilp32 } */
+/* { dg-options "-Wno-long-long" } */
+
+#pragma pack(push, 1)
+
+#include "darwin-structs-0.h"
+
+int tcd[sizeof(cd) != 9 ? -1 : 1];
+int acd[__alignof__(cd) != 1 ? -1 : 1];
+
+int sdc[sizeof(dc) != 9 ? -1 : 1];
+int adc[__alignof__(dc) != 1 ? -1 : 1];
+
+int scL[sizeof(cL) != 9 ? -1 : 1];
+int acL[__alignof__(cL) != 1 ? -1 : 1];
+
+int sLc[sizeof(Lc) != 9 ? -1 : 1];
+int aLc[__alignof__(Lc) != 1 ? -1 : 1];
+
+int scD[sizeof(cD) != 17 ? -1 : 1];
+int acD[__alignof__(cD) != 1 ? -1 : 1];
+
+int sDc[sizeof(Dc) != 17 ? -1 : 1];
+int aDc[__alignof__(Dc) != 1 ? -1 : 1];
+
+#pragma pack(pop)
diff --git a/gcc/testsuite/gcc.target/powerpc/darwin-abi-13-2.c b/gcc/testsuite/gcc.target/powerpc/darwin-abi-13-2.c
new file mode 100644
index 00000000000..3bd52c0a8f8
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/darwin-abi-13-2.c
@@ -0,0 +1,27 @@
+/* { dg-do compile { target powerpc*-*-darwin* } } */
+/* { dg-require-effective-target ilp32 } */
+/* { dg-options "-Wno-long-long" } */
+
+#pragma pack(push, 2)
+
+#include "darwin-structs-0.h"
+
+int tcd[sizeof(cd) != 10 ? -1 : 1];
+int acd[__alignof__(cd) != 2 ? -1 : 1];
+
+int sdc[sizeof(dc) != 10 ? -1 : 1];
+int adc[__alignof__(dc) != 2 ? -1 : 1];
+
+int scL[sizeof(cL) != 10 ? -1 : 1];
+int acL[__alignof__(cL) != 2 ? -1 : 1];
+
+int sLc[sizeof(Lc) != 10 ? -1 : 1];
+int aLc[__alignof__(Lc) != 2 ? -1 : 1];
+
+int scD[sizeof(cD) != 18 ? -1 : 1];
+int acD[__alignof__(cD) != 2 ? -1 : 1];
+
+int sDc[sizeof(Dc) != 18 ? -1 : 1];
+int aDc[__alignof__(Dc) != 2 ? -1 : 1];
+
+#pragma pack(pop)
diff --git a/gcc/testsuite/gcc.target/powerpc/darwin-structs-0.h b/gcc/testsuite/gcc.target/powerpc/darwin-structs-0.h
new file mode 100644
index 00000000000..1db44f7a808
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/darwin-structs-0.h
@@ -0,0 +1,29 @@
+typedef struct _cd {
+ char c;
+ double d;
+} cd;
+
+typedef struct _dc {
+ double d;
+ char c;
+} dc;
+
+typedef struct _cL {
+ char c;
+ long long L;
+} cL;
+
+typedef struct _Lc {
+ long long L;
+ char c;
+} Lc;
+
+typedef struct _cD {
+ char c;
+ long double D;
+} cD;
+
+typedef struct _Dc {
+ long double D;
+ char c;
+} Dc;