tcg/optimize: fix uninitialized variable

The variables uext_opc and sext_opc are used without initialization if
TCG_TARGET_extract_i{32,64}_valid returns false.  The result, depending
on the compiler, might be the generation of extract and sextract opcodes
with invalid offset and count, or just random data in the TCG opcode
stream.

Fixes: ceb9ee06b71 ("tcg/optimize: Handle TCG_COND_TST{EQ,NE}", 2024-02-03)
Cc: Richard Henderson <pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20240228110641.287205-1-pbonzini@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

diff --git a/tcg/optimize.c b/tcg/optimize.c
index 79e701652bfef75d0661e8cd66bcfbeb23de5905..752cc5c56b671eac78fec6a04270518b6cff4581 100644 (file)
--- a/tcg/optimize.c
+++ b/tcg/optimize.c
@@ -2102,7 +2102,8 @@ static bool fold_remainder(OptContext *ctx, TCGOp *op)
 
 static void fold_setcond_tst_pow2(OptContext *ctx, TCGOp *op, bool neg)
 {
-    TCGOpcode and_opc, sub_opc, xor_opc, neg_opc, shr_opc, uext_opc, sext_opc;
+    TCGOpcode and_opc, sub_opc, xor_opc, neg_opc, shr_opc;
+    TCGOpcode uext_opc = 0, sext_opc = 0;
     TCGCond cond = op->args[3];
     TCGArg ret, src1, src2;
     TCGOp *op2;