RFR: 8285923: [REDO] JDK-8285802 AArch64: Consistently handle offsets in MacroAssembler as 64-bit quantities

[Andrew Haley]

It is with some trepidation that I post this after breaking things last time. However, I think I've tested this as much as it can be tested.

The change from last time around is this:


+++ b/src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp
@@ -2192,11 +2192,13 @@ void MacroAssembler::unimplemented(const char* what) {
 
 // If a constant does not fit in an immediate field, generate some
 // number of MOV instructions and then perform the operation.
-void MacroAssembler::wrap_add_sub_imm_insn(Register Rd, Register Rn, unsigned imm,
+void MacroAssembler::wrap_add_sub_imm_insn(Register Rd, Register Rn, uint64_t imm,
                                            add_sub_imm_insn insn1,
-                                           add_sub_reg_insn insn2) {
+                                           add_sub_reg_insn insn2,
+                                           bool is32) {
   assert(Rd != zr, "Rd = zr and not setting flags?");
-  if (operand_valid_for_add_sub_immediate((int)imm)) {
+  bool fits = operand_valid_for_add_sub_immediate(is32 ? (int32_t)imm : imm);
+  if (fits) {
     (this->*insn1)(Rd, Rn, imm);


After this patch, when an add/sub instruction has a 32-bit (rather than a 64-bit) operand, we truncate the operand to signed int. We do this because `operand_valid_for_add_sub_immediate()` takes a 64-bit signed operand, but if the instruction is only 32 bits wide we must ignore the upper 32 bits. Therefore, `wrap_add_sub_imm_insn()` needs to know the operand size in order to sign extend the operand correctly.

Tested tier1-3, tier4 is still running but no regressions yet.

-------------

Commit messages:
 - 8285923: [REDO] JDK-8285802 AArch64: Consistently handle offsets in MacroAssembler as 64-bit quantities

Changes: https://git.openjdk.java.net/jdk/pull/8554/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8554&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8285923
  Stats: 29 lines in 3 files changed: 4 ins; 0 del; 25 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8554.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8554/head:pull/8554

PR: https://git.openjdk.java.net/jdk/pull/8554