Recognize ROL/ROR patterns

dstogov · May 7, 2024 · 005f7b5 · 005f7b5
1 parent 48687e2
commit 005f7b5
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diff --git a/ir_fold.h b/ir_fold.h
@@ -2838,6 +2838,46 @@ IR_FOLD(XOR(XOR, _))
 	IR_FOLD_NEXT;
 }
 
+/* ROL/ROR */
+IR_FOLD(OR(SHL, SHR))
+IR_FOLD(OR(SHR, SHL))
+IR_FOLD(ADD(SHL, SHR))
+IR_FOLD(ADD(SHR, SHL))
+{
+	if (op1_insn->op1 == op2_insn->op1) {
+		if (IR_IS_CONST_REF(op1_insn->op2) && IR_IS_CONST_REF(op2_insn->op2)) {
+			if (ctx->ir_base[op1_insn->op2].val.u64 + ctx->ir_base[op2_insn->op2].val.u64 ==
+					ir_type_size[IR_OPT_TYPE(opt)] * 8) {
+				/* (x << c) | (x >> (32 - c)) -> ROL(x, c) */
+				op1 = op1_insn->op1;
+				op2 = op1_insn->op2;
+				opt = op1_insn->opt + 3; /* SHL -> ROL, SHR -> ROR */
+				IR_FOLD_RESTART;
+			}
+		} else if (ctx->ir_base[op2_insn->op2].op == IR_SUB
+				&& IR_IS_CONST_REF(ctx->ir_base[op2_insn->op2].op1)
+				&& ctx->ir_base[op2_insn->op2].op2 == op1_insn->op2
+				&& ctx->ir_base[ctx->ir_base[op2_insn->op2].op1].val.u64 == ir_type_size[IR_OPT_TYPE(opt)] * 8) {
+			/* (x << y) | (x >> (32 - y)) -> ROL(x, y) */
+			op1 = op1_insn->op1;
+			op2 = op1_insn->op2;
+			opt = op1_insn->opt + 3; /* SHL -> ROL, SHR -> ROR */
+			IR_FOLD_RESTART;
+		} else if (ctx->ir_base[op1_insn->op2].op == IR_SUB
+				&& IR_IS_CONST_REF(ctx->ir_base[op1_insn->op2].op1)
+				&& ctx->ir_base[op1_insn->op2].op2 == op2_insn->op2
+				&& ctx->ir_base[ctx->ir_base[op1_insn->op2].op1].val.u64 == ir_type_size[IR_OPT_TYPE(opt)] * 8) {
+			/* (x << (32 - y)) | (x >> y) -> ROR(x, y) */
+			op1 = op2_insn->op1;
+			op2 = op2_insn->op2;
+			opt = op2_insn->opt + 3; /* SHL -> ROL, SHR -> ROR */
+			IR_FOLD_RESTART;
+		}
+	}
+	IR_FOLD_NEXT;
+}
+
+
 /* Swap operands (move lower ref to op2) for better CSE */
 IR_FOLD(ADD(_, _))
 IR_FOLD(MUL(_, _))

diff --git a/tests/combine_rol_ror_001.irt b/tests/combine_rol_ror_001.irt
@@ -0,0 +1,30 @@
+--TEST--
+001: Combine ROL/ROR
+--ARGS--
+-O2 --save
+--CODE--
+{
+	uintptr_t c_1 = 0;
+	bool c_2 = 0;
+	bool c_3 = 1;
+	int32_t c_4 = 32;
+	l_1 = START(l_12);
+	int32_t d_2 = PARAM(l_1, "x", 0);
+	int32_t d_3 = PARAM(l_1, "y", 1);
+	int32_t d_4 = SHL(d_2, d_3);
+	int32_t d_5 = SUB(c_4, d_3);
+	int32_t d_6 = SHR(d_2, d_5);
+	int32_t d_7 = OR(d_4, d_6);
+	l_12 = RETURN(l_1, d_7);
+}
+--EXPECT--
+{
+	uintptr_t c_1 = 0;
+	bool c_2 = 0;
+	bool c_3 = 1;
+	l_1 = START(l_5);
+	int32_t d_2 = PARAM(l_1, "x", 0);
+	int32_t d_3 = PARAM(l_1, "y", 1);
+	int32_t d_4 = ROL(d_2, d_3);
+	l_5 = RETURN(l_1, d_4);
+}
diff --git a/tests/combine_rol_ror_002.irt b/tests/combine_rol_ror_002.irt
@@ -0,0 +1,30 @@
+--TEST--
+001: Combine ROL/ROR
+--ARGS--
+-O2 --save
+--CODE--
+{
+	uintptr_t c_1 = 0;
+	bool c_2 = 0;
+	bool c_3 = 1;
+	int32_t c_4 = 32;
+	l_1 = START(l_12);
+	int32_t d_2 = PARAM(l_1, "x", 0);
+	int32_t d_3 = PARAM(l_1, "y", 1);
+	int32_t d_4 = SUB(c_4, d_3);
+	int32_t d_5 = SHL(d_2, d_4);
+	int32_t d_6 = SHR(d_2, d_3);
+	int32_t d_7 = OR(d_5, d_6);
+	l_12 = RETURN(l_1, d_7);
+}
+--EXPECT--
+{
+	uintptr_t c_1 = 0;
+	bool c_2 = 0;
+	bool c_3 = 1;
+	l_1 = START(l_5);
+	int32_t d_2 = PARAM(l_1, "x", 0);
+	int32_t d_3 = PARAM(l_1, "y", 1);
+	int32_t d_4 = ROR(d_2, d_3);
+	l_5 = RETURN(l_1, d_4);
+}
diff --git a/tests/combine_rol_ror_003.irt b/tests/combine_rol_ror_003.irt
@@ -0,0 +1,29 @@
+--TEST--
+001: Combine ROL/ROR
+--ARGS--
+-O2 --save
+--CODE--
+{
+	uintptr_t c_1 = 0;
+	bool c_2 = 0;
+	bool c_3 = 1;
+	int32_t c_4 = 12;
+	int32_t c_5 = 20;
+	l_1 = START(l_12);
+	int32_t d_2 = PARAM(l_1, "x", 0);
+	int32_t d_3 = SHL(d_2, c_4);
+	int32_t d_4 = SHR(d_2, c_5);
+	int32_t d_5 = OR(d_3, d_4);
+	l_12 = RETURN(l_1, d_5);
+}
+--EXPECT--
+{
+	uintptr_t c_1 = 0;
+	bool c_2 = 0;
+	bool c_3 = 1;
+	int32_t c_4 = 12;
+	l_1 = START(l_4);
+	int32_t d_2 = PARAM(l_1, "x", 0);
+	int32_t d_3 = ROL(d_2, c_4);
+	l_4 = RETURN(l_1, d_3);
+}