rs6000: Fix stack clash for big residuals (PR85287)

The stack clash protection code had a logic error in how it decided
whether to put the final update size in a register, or to emit it
directly in an insn.  This fixes it.  It also tidies some surrounding
code.

	PR target/85287
	* gcc/config/rs6000/rs6000.md (allocate_stack): Put the residual size
	for stack clash protection in a register whenever we need it to be in
	a register.

From-SVN: r259299

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 2031dc7..480af2a 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,11 @@
 2018-04-10  Segher Boessenkool  <segher@kernel.crashing.org>
 
+       * gcc/config/rs6000/rs6000.md (allocate_stack): Put the residual size
+       for stack clash protection in a register whenever we need it to be in
+       a register.
+
+2018-04-10  Segher Boessenkool  <segher@kernel.crashing.org>
+
        * common/config/rs6000/rs6000-common.c (rs6000_option_init_struct):
        Enable -fasynchronous-unwind-tables by default if OBJECT_FORMAT_ELF.
 

diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
index d08e232..b07e5bd 100644 (file)
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -9783,14 +9783,12 @@
       /* Now handle residuals.  We just have to set operands[1] correctly
         and let the rest of the expander run.  */
       operands[1] = residual;
-      if (!CONST_INT_P (residual))
-       operands[1] = force_reg (Pmode, operands[1]);
     }
 
-  if (GET_CODE (operands[1]) != CONST_INT
-      || INTVAL (operands[1]) < -32767
-      || INTVAL (operands[1]) > 32768)
+  if (!(CONST_INT_P (operands[1])
+       && IN_RANGE (INTVAL (operands[1]), -32767, 32768)))
     {
+      operands[1] = force_reg (Pmode, operands[1]);
       neg_op0 = gen_reg_rtx (Pmode);
       if (TARGET_32BIT)
        emit_insn (gen_negsi2 (neg_op0, operands[1]));
@@ -9798,7 +9796,7 @@
        emit_insn (gen_negdi2 (neg_op0, operands[1]));
     }
   else
-    neg_op0 = GEN_INT (- INTVAL (operands[1]));
+    neg_op0 = GEN_INT (-INTVAL (operands[1]));
 
   insn = emit_insn ((* ((TARGET_32BIT) ? gen_movsi_update_stack
                                       : gen_movdi_di_update_stack))