[Bug 1918026] [NEW] RISCV64 32-bit AMOs incorrectly simulated

[Ryan Macnak]

Public bug reported:

Version: qemu-riscv64 version 4.2.1 (Debian 1:4.2-3ubuntu6.14)

test:
  amomaxu.w a0, a1, (a0)
  ret

int32_t* value = -7;
EXPECT_EQ(-7, test(&value, -11));
EXPECT_EQ(-7, value);  // FAIL, saw -11
EXPECT_EQ(-7, test(&value, -7));
EXPECT_EQ(-7, value);  // FAIL, raw -11
EXPECT_EQ(-7, test(&value, -4));
EXPECT_EQ(-4, value);

test:
  amomax.w a0, a1, (a0)
  ret

int32_t* value = -7;
EXPECT_EQ(-7, test(&value, -11));
EXPECT_EQ(-7, value);
EXPECT_EQ(-7, test(&value, -7));
EXPECT_EQ(-7, value);
EXPECT_EQ(-7, test(&value, -4));
EXPECT_EQ(-4, value);  // FAIL, saw -7

I suspect that trans_amo<op>_w should be using
tcg_gen_atomic_fetch_<op>_i32 instead of tcg_gen_atomic_fetch_<op>_tl.

** Affects: qemu
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1918026

Title:
  RISCV64 32-bit AMOs incorrectly simulated

Status in QEMU:
  New

Bug description:
  Version: qemu-riscv64 version 4.2.1 (Debian 1:4.2-3ubuntu6.14)

  test:
    amomaxu.w a0, a1, (a0)
    ret

  int32_t* value = -7;
  EXPECT_EQ(-7, test(&value, -11));
  EXPECT_EQ(-7, value);  // FAIL, saw -11
  EXPECT_EQ(-7, test(&value, -7));
  EXPECT_EQ(-7, value);  // FAIL, raw -11
  EXPECT_EQ(-7, test(&value, -4));
  EXPECT_EQ(-4, value);

  test:
    amomax.w a0, a1, (a0)
    ret

  int32_t* value = -7;
  EXPECT_EQ(-7, test(&value, -11));
  EXPECT_EQ(-7, value);
  EXPECT_EQ(-7, test(&value, -7));
  EXPECT_EQ(-7, value);
  EXPECT_EQ(-7, test(&value, -4));
  EXPECT_EQ(-4, value);  // FAIL, saw -7

  I suspect that trans_amo<op>_w should be using
  tcg_gen_atomic_fetch_<op>_i32 instead of tcg_gen_atomic_fetch_<op>_tl.

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