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* [gcc(refs/vendors/redhat/heads/gcc-8-branch)] aarch64: Tweak post-RA handling of CONST_INT moves [PR98136]
@ 2021-05-14 14:54 Jakub Jelinek
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From: Jakub Jelinek @ 2021-05-14 14:54 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:6331cd93c5054d0ac598e48b2ed05649a399ee53
commit 6331cd93c5054d0ac598e48b2ed05649a399ee53
Author: Richard Sandiford <richard.sandiford@arm.com>
Date: Mon Apr 26 09:36:47 2021 +0100
aarch64: Tweak post-RA handling of CONST_INT moves [PR98136]
This PR is a regression caused by r8-5967, where we replaced
a call to aarch64_internal_mov_immediate in aarch64_add_offset
with a call to aarch64_force_temporary, which in turn uses the
normal emit_move_insn{,_1} routines.
The problem is that aarch64_add_offset can be called while
outputting a thunk, where we require all instructions to be
valid without splitting. However, the move expanders were
not splitting CONST_INT moves themselves.
I think the right fix is to make the move expanders work
even in this scenario, rather than require callers to handle
it as a special case.
gcc/
PR target/98136
* config/aarch64/aarch64.md (mov<mode>): Pass multi-instruction
CONST_INTs to aarch64_expand_mov_immediate when called after RA.
gcc/testsuite/
PR target/98136
* g++.dg/pr98136.C: New test.
(cherry picked from commit 48c79f054bf435051c95ee093c45a0f8c9de5b4e)
Diff:
---
gcc/config/aarch64/aarch64.md | 17 +++++++++++++----
gcc/testsuite/g++.dg/pr98136.C | 26 ++++++++++++++++++++++++++
2 files changed, 39 insertions(+), 4 deletions(-)
diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
index ea1319c56a4..bfcc1a2a18b 100644
--- a/gcc/config/aarch64/aarch64.md
+++ b/gcc/config/aarch64/aarch64.md
@@ -986,10 +986,19 @@
if (GET_CODE (operands[0]) == MEM && operands[1] != const0_rtx)
operands[1] = force_reg (<MODE>mode, operands[1]);
- /* FIXME: RR we still need to fix up what we are doing with
- symbol_refs and other types of constants. */
- if (CONSTANT_P (operands[1])
- && !CONST_INT_P (operands[1]))
+ /* Lower moves of symbolic constants into individual instructions.
+ Doing this now is sometimes necessary for correctness, since some
+ sequences require temporary pseudo registers. Lowering now is also
+ often better for optimization, since more RTL passes get the
+ chance to optimize the individual instructions.
+
+ When called after RA, also split multi-instruction moves into
+ smaller pieces now, since we can't be sure that sure that there
+ will be a following split pass. */
+ if (CONST_INT_P (operands[1])
+ ? (reload_completed
+ && !aarch64_mov_imm_operand (operands[1], <MODE>mode))
+ : CONSTANT_P (operands[1]))
{
aarch64_expand_mov_immediate (operands[0], operands[1]);
DONE;
diff --git a/gcc/testsuite/g++.dg/pr98136.C b/gcc/testsuite/g++.dg/pr98136.C
new file mode 100644
index 00000000000..f3c27f6b09f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/pr98136.C
@@ -0,0 +1,26 @@
+// { dg-do compile { target { ilp32 || lp64 } } }
+
+struct AddIn
+{
+ virtual ~AddIn() {}
+ virtual void AddInCall()=0;
+};
+
+struct Base
+{
+ char b[32*1024*1024]; // Anything bigger than 16mb causes internal compiler error
+ virtual ~Base() {}
+};
+
+struct Deriv : public Base,
+ public AddIn
+{
+ void AddInCall() {}
+};
+
+int main (int argc, char **argv)
+{
+ Deriv deriv;
+ deriv.AddInCall();
+ return 0;
+}
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