}
expand_operands (treeop0, treeop1, subtarget, &op0, &op1, EXPAND_NORMAL);
+
+ /* Expand X*Y as X&-Y when Y must be zero or one. */
+ if (SCALAR_INT_MODE_P (mode))
+ {
+ bool bit0_p = tree_nonzero_bits (treeop0) == 1;
+ bool bit1_p = tree_nonzero_bits (treeop1) == 1;
+
+ /* Expand X*Y as X&Y when both X and Y must be zero or one. */
+ if (bit0_p && bit1_p)
+ return REDUCE_BIT_FIELD (expand_and (mode, op0, op1, target));
+
+ if (bit0_p || bit1_p)
+ {
+ bool speed = optimize_insn_for_speed_p ();
+ int cost = add_cost (speed, mode) + neg_cost (speed, mode);
+ struct algorithm algorithm;
+ enum mult_variant variant;
+ if (CONST_INT_P (op1)
+ ? !choose_mult_variant (mode, INTVAL (op1),
+ &algorithm, &variant, cost)
+ : cost < mul_cost (speed, mode))
+ {
+ target = bit0_p ? expand_and (mode, negate_rtx (mode, op0),
+ op1, target)
+ : expand_and (mode, op0,
+ negate_rtx (mode, op1),
+ target);
+ return REDUCE_BIT_FIELD (target);
+ }
+ }
+ }
+
return REDUCE_BIT_FIELD (expand_mult (mode, op0, op1, target, unsignedp));
case TRUNC_MOD_EXPR:
--- /dev/null
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+#if __SIZEOF_INT__ == 4
+unsigned int foo(unsigned int a, unsigned int b)
+{
+ return (a >> 31) * b;
+}
+
+int bar(int a, int b)
+{
+ return -(a >> 31) * b;
+}
+
+int baz(int a, int b)
+{
+ int c = a >> 31;
+ int d = -c;
+ return d * b;
+}
+
+unsigned int pin(int a, unsigned int b)
+{
+ unsigned int t = a & 1;
+ return t * b;
+}
+#endif
+
+#if __SIZEOF_LONG_LONG__ == 8
+unsigned long long fool(unsigned long long a, unsigned long long b)
+{
+ return (a >> 63) * b;
+}
+
+long long barl (long long a, long long b)
+{
+ return -(a >> 63) * b;
+}
+
+long long bazl (long long a, long long b)
+{
+ long long c = a >> 63;
+ long long d = -c;
+ return d * b;
+}
+
+unsigned long long pinl(long long a, unsigned long long b)
+{
+ unsigned long long t = a & 1;
+ return t * b;
+}
+#endif
+
+/* { dg-final { scan-assembler-not "imul" } } */