Fix undefined shift behavior found by ASAN.

Shift by negative numbers is undefined.
Shift by numbers larger than the destination bit width is undefined.

PiperOrigin-RevId: 714235980
Change-Id: I590eae0e1f4f89991738345bda30f3c98018d065

riscv/test/riscv_vector_basic_bit_manipulation_test.cc

diff --git a/riscv/test/riscv_vector_basic_bit_manipulation_test.cc b/riscv/test/riscv_vector_basic_bit_manipulation_test.cc
index 923f3cd..7ddd73d 100644
--- a/riscv/test/riscv_vector_basic_bit_manipulation_test.cc
+++ b/riscv/test/riscv_vector_basic_bit_manipulation_test.cc
@@ -130,10 +130,11 @@
   tester->BinaryOpTestHelperVV<T, T, T>(
       absl::StrCat("Vrol", sizeof(T) * 8, "vv"), /*sew*/ sizeof(T) * 8,
       tester->instruction(), [](T vs2, T vs1) -> T {
-        T rotate_mask = sizeof(T) * 8 - 1;
-        T rotate_amount = (vs1 & rotate_mask);
-        return (vs2 << rotate_amount) |
-               (vs2 >> (sizeof(T) * 8 - rotate_amount));
+        T bitsize = sizeof(T) * 8;
+        T shift_mask = bitsize - 1;
+        uint8_t shiftl_amount = vs1 & shift_mask;
+        uint8_t shiftr_amount = (bitsize - shiftl_amount) & shift_mask;
+        return (vs2 << shiftl_amount) | (vs2 >> shiftr_amount);
       });
 }
 
@@ -145,10 +146,11 @@
   tester->BinaryOpTestHelperVX<T, T, T>(
       absl::StrCat("Vrol", sizeof(T) * 8, "vx"), /*sew*/ sizeof(T) * 8,
       tester->instruction(), [](T vs2, T rs1) -> T {
-        T rotate_mask = sizeof(T) * 8 - 1;
-        T rotate_amount = (rs1 & rotate_mask);
-        return (vs2 << rotate_amount) |
-               (vs2 >> (sizeof(T) * 8 - rotate_amount));
+        T bitsize = sizeof(T) * 8;
+        T shift_mask = bitsize - 1;
+        uint8_t shiftl_amount = rs1 & shift_mask;
+        uint8_t shiftr_amount = (bitsize - shiftl_amount) & shift_mask;
+        return (vs2 << shiftl_amount) | (vs2 >> shiftr_amount);
       });
 }
 
@@ -160,10 +162,11 @@
   tester->BinaryOpTestHelperVV<T, T, T>(
       absl::StrCat("Vror", sizeof(T) * 8, "vv"), /*sew*/ sizeof(T) * 8,
       tester->instruction(), [](T vs2, T vs1) -> T {
-        T rotate_mask = sizeof(T) * 8 - 1;
-        T rotate_amount = (vs1 & rotate_mask);
-        return (vs2 >> rotate_amount) |
-               (vs2 << (sizeof(T) * 8 - rotate_amount));
+        T bitsize = sizeof(T) * 8;
+        T shift_mask = bitsize - 1;
+        uint8_t shiftr_amount = vs1 & shift_mask;
+        uint8_t shiftl_amount = (bitsize - shiftr_amount) & shift_mask;
+        return (vs2 << shiftl_amount) | (vs2 >> shiftr_amount);
       });
 }
 
@@ -175,10 +178,11 @@
   tester->BinaryOpTestHelperVV<T, T, T>(
       absl::StrCat("Vror", sizeof(T) * 8, "vx"), /*sew*/ sizeof(T) * 8,
       tester->instruction(), [](T vs2, T rs1) -> T {
-        T rotate_mask = sizeof(T) * 8 - 1;
-        T rotate_amount = (rs1 & rotate_mask);
-        return (vs2 >> rotate_amount) |
-               (vs2 << (sizeof(T) * 8 - rotate_amount));
+        T bitsize = sizeof(T) * 8;
+        T shift_mask = bitsize - 1;
+        uint8_t shiftr_amount = rs1 & shift_mask;
+        uint8_t shiftl_amount = (bitsize - shiftr_amount) & shift_mask;
+        return (vs2 << shiftl_amount) | (vs2 >> shiftr_amount);
       });
 }
 
@@ -190,10 +194,11 @@
   tester->BinaryOpTestHelperVV<T, T, T>(
       absl::StrCat("Vror", sizeof(T) * 8, "vi"), /*sew*/ sizeof(T) * 8,
       tester->instruction(), [](T vs2, T imm) -> T {
-        T rotate_mask = sizeof(T) * 8 - 1;
-        T rotate_amount = (imm & rotate_mask);
-        return (vs2 >> rotate_amount) |
-               (vs2 << (sizeof(T) * 8 - rotate_amount));
+        T bitsize = sizeof(T) * 8;
+        T shift_mask = bitsize - 1;
+        uint8_t shiftr_amount = imm & shift_mask;
+        uint8_t shiftl_amount = (bitsize - shiftr_amount) & shift_mask;
+        return (vs2 << shiftl_amount) | (vs2 >> shiftr_amount);
       });
 }
 
@@ -262,7 +267,7 @@
       absl::StrCat("Vwsll", sizeof(T) * 8, "vv"), /*sew*/ sizeof(T) * 8,
       tester->instruction(), [](T vs2, T vs1) -> WT {
         T shift_mask = 2 * 8 * sizeof(T) - 1;
-        T shift_amount = (vs1 & shift_mask);
+        T shift_amount = vs1 & shift_mask;
         return static_cast<WT>(vs2) << shift_amount;
       });
 }
@@ -277,7 +282,7 @@
       absl::StrCat("Vwsll", sizeof(T) * 8, "vx"), /*sew*/ sizeof(T) * 8,
       tester->instruction(), [](T vs2, T rs1) -> WT {
         T shift_mask = 2 * 8 * sizeof(T) - 1;
-        T shift_amount = (rs1 & shift_mask);
+        T shift_amount = rs1 & shift_mask;
         return static_cast<WT>(vs2) << shift_amount;
       });
 }
@@ -292,7 +297,7 @@
       absl::StrCat("Vwsll", sizeof(T) * 8, "vi"), /*sew*/ sizeof(T) * 8,
       tester->instruction(), [](T vs2, T imm) -> WT {
         T shift_mask = 2 * 8 * sizeof(T) - 1;
-        T shift_amount = (imm & shift_mask);
+        T shift_amount = imm & shift_mask;
         return static_cast<WT>(vs2) << shift_amount;
       });
 }