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[PATCH] tcg/s390: Fix compare instruction from extended-immediate facili


From: Philippe Mathieu-Daudé
Subject: [PATCH] tcg/s390: Fix compare instruction from extended-immediate facility
Date: Thu, 4 Feb 2021 19:29:02 +0100

The code is currently comparing c2 to the type promotion of
uint32_t and int32_t. That is, the conversion rules are as:

  (common_type) c2 == (common_type) (uint32_t)
                        (is_unsigned
                        ? (uint32_t)c2
                        : (uint32_t)(int32_t)c2)

In the signed case we lose the desired sign extensions because
of the argument promotion rules of the ternary operator.

Solve the problem by doing the round-trip parsing through the
intermediate type and back to the desired common type (all at
one expression).

Fixes: a534bb15f30 ("tcg/s390: Use constant pool for cmpi")
Reported-by: Miroslav Rezanina <mrezanin@redhat.com>
Reported-by: Richard W.M. Jones <rjones@redhat.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Suggested-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 tcg/s390/tcg-target.c.inc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tcg/s390/tcg-target.c.inc b/tcg/s390/tcg-target.c.inc
index b67470137c4..695d7ee6523 100644
--- a/tcg/s390/tcg-target.c.inc
+++ b/tcg/s390/tcg-target.c.inc
@@ -1067,7 +1067,7 @@ static int tgen_cmp(TCGContext *s, TCGType type, TCGCond 
c, TCGReg r1,
                 op = (is_unsigned ? RIL_CLFI : RIL_CFI);
                 tcg_out_insn_RIL(s, op, r1, c2);
                 goto exit;
-            } else if (c2 == (is_unsigned ? (uint32_t)c2 : (int32_t)c2)) {
+            } else if (c2 == (is_unsigned ? (TCGArg)(uint32_t)c2 : 
(TCGArg)(int32_t)c2)) {
                 op = (is_unsigned ? RIL_CLGFI : RIL_CGFI);
                 tcg_out_insn_RIL(s, op, r1, c2);
                 goto exit;
-- 
2.26.2




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