From f04146a96be59b603ca36eac0bb4f244bc29c7af Mon Sep 17 00:00:00 2001 From: Alan Modra Date: Wed, 16 Apr 2025 07:12:46 +0930 Subject: [PATCH] loongarch gas resolving constant expressions The test added in commit 4fe96ddaf614 results in an asan complaint: loongarch-parse.y:225:16: runtime error: left shift of negative value -1 To avoid the complaint, perform left shifts as unsigned (which gives the same result on 2's complement machines). Do the same for addition, subtraction and multiplication. Furthermore, warn on divide/modulus by zero. --- gas/config/loongarch-parse.y | 32 ++++++++++++++++++++++---------- 1 file changed, 22 insertions(+), 10 deletions(-) diff --git a/gas/config/loongarch-parse.y b/gas/config/loongarch-parse.y index 97055fe42c3..b75040c14b1 100644 --- a/gas/config/loongarch-parse.y +++ b/gas/config/loongarch-parse.y @@ -207,29 +207,41 @@ emit_bin (int op) switch (op) { case '*': - opr1 = opr1 * opr2; + opr1 = (valueT) opr1 * (valueT) opr2; break; case '/': - opr1 = opr1 / opr2; + if (opr2 == 0) + { + as_warn (_("Divide by zero!")); + opr1 = 0; + } + else + opr1 = opr1 / opr2; break; case '%': - opr1 = opr1 % opr2; + if (opr2 == 0) + { + as_warn (_("Divide by zero!")); + opr1 = 0; + } + else + opr1 = opr1 % opr2; break; case '+': - opr1 = opr1 + opr2; + opr1 = (valueT) opr1 + (valueT) opr2; break; case '-': - opr1 = opr1 - opr2; + opr1 = (valueT) opr1 - (valueT) opr2; break; case LEFT_OP: - opr1 = opr1 << opr2; + opr1 = (valueT) opr1 << opr2; break; case RIGHT_OP: if (opr1 < 0) - as_warn(_("Right shift of negative numbers may be changed " - "from arithmetic right shift to logical right shift!")); - /* Algorithm right shift. */ - opr1 = (offsetT)opr1 >> (offsetT)opr2; + as_warn (_("Right shift of negative numbers may be changed " + "from arithmetic right shift to logical right shift!")); + /* Arithmetic right shift. */ + opr1 = opr1 >> opr2; break; case '<': opr1 = opr1 < opr2; -- 2.39.5