[to-be-committed,RISC-V] Improve usage of slli.uw in constant synthesis

diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index 049f8f8cb9f..a1e5a014bed 100644
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -819,13 +819,14 @@  riscv_build_integer_1 (struct riscv_integer_op codes[RISCV_MAX_INTEGER_OPS],
 				  & ~HOST_WIDE_INT_C (0x80000000)))))
 	shift -= IMM_BITS, x <<= IMM_BITS;
 
-      /* Adjust X if it isn't a LUI operand in isolation, but we can use
-	 a subsequent "uw" instruction form to mask off the undesirable
-	 bits.  */
+      /* If X has bits 32..63 clear and bit 31 set, then go ahead and mark
+	 it as desiring a "uw" operation for the shift.  That way we can have
+	 LUI+ADDI to generate the constant, then shift it into position
+	 clearing out the undesirable bits.  */
       if (!LUI_OPERAND (x)
 	  && TARGET_64BIT
 	  && TARGET_ZBA
-	  && LUI_OPERAND (x & ~HOST_WIDE_INT_C (0x80000000UL)))
+	  && clz_hwi (x) == 32)
 	{
 	  x = sext_hwi (x, 32);
 	  use_uw = true;
diff --git a/gcc/testsuite/gcc.target/riscv/synthesis-5.c b/gcc/testsuite/gcc.target/riscv/synthesis-5.c
new file mode 100644
index 00000000000..4d81565b563
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/synthesis-5.c
@@ -0,0 +1,294 @@ 
+/* { dg-do compile } */
+/* { dg-require-effective-target rv64 } */
+
+/* We aggressively skip as we really just need to test the basic synthesis
+   which shouldn't vary based on the optimization level.  -O1 seems to work
+   and eliminates the usual sources of extraneous dead code that would throw
+   off the counts.  */
+/* { dg-skip-if "" { *-*-* } { "-O0" "-Og" "-O2" "-O3" "-Os" "-Oz" "-flto" } } */
+/* { dg-options "-march=rv64gc_zba_zbb_zbs" } */
+
+/* Rather than test for a specific synthesis of all these constants or
+   having thousands of tests each testing one variant, we just test the
+   total number of instructions.
+
+   This isn't expected to change much and any change is worthy of a look.  */
+/* { dg-final { scan-assembler-times "\\t(add|addi|bseti|li|ret|sh1add|sh2add|sh3add|slli)" 556 } } */
+
+unsigned long foo_0x80180001000(void) { return 0x80180001000UL; }
+
+unsigned long foo_0x80280001000(void) { return 0x80280001000UL; }
+
+unsigned long foo_0x80480001000(void) { return 0x80480001000UL; }
+
+unsigned long foo_0x80880001000(void) { return 0x80880001000UL; }
+
+unsigned long foo_0x81080001000(void) { return 0x81080001000UL; }
+
+unsigned long foo_0x82080001000(void) { return 0x82080001000UL; }
+
+unsigned long foo_0x84080001000(void) { return 0x84080001000UL; }
+
+unsigned long foo_0x88080001000(void) { return 0x88080001000UL; }
+
+unsigned long foo_0x90080001000(void) { return 0x90080001000UL; }
+
+unsigned long foo_0xa0080001000(void) { return 0xa0080001000UL; }
+
+unsigned long foo_0x80300001000(void) { return 0x80300001000UL; }
+
+unsigned long foo_0x80500001000(void) { return 0x80500001000UL; }
+
+unsigned long foo_0x80900001000(void) { return 0x80900001000UL; }
+
+unsigned long foo_0x81100001000(void) { return 0x81100001000UL; }
+
+unsigned long foo_0x82100001000(void) { return 0x82100001000UL; }
+
+unsigned long foo_0x84100001000(void) { return 0x84100001000UL; }
+
+unsigned long foo_0x88100001000(void) { return 0x88100001000UL; }
+
+unsigned long foo_0x90100001000(void) { return 0x90100001000UL; }
+
+unsigned long foo_0xa0100001000(void) { return 0xa0100001000UL; }
+
+unsigned long foo_0xc0100001000(void) { return 0xc0100001000UL; }
+
+unsigned long foo_0x80600001000(void) { return 0x80600001000UL; }
+
+unsigned long foo_0x80a00001000(void) { return 0x80a00001000UL; }
+
+unsigned long foo_0x81200001000(void) { return 0x81200001000UL; }
+
+unsigned long foo_0x82200001000(void) { return 0x82200001000UL; }
+
+unsigned long foo_0x84200001000(void) { return 0x84200001000UL; }
+
+unsigned long foo_0x88200001000(void) { return 0x88200001000UL; }
+
+unsigned long foo_0xa0200001000(void) { return 0xa0200001000UL; }
+
+unsigned long foo_0xc0200001000(void) { return 0xc0200001000UL; }
+
+unsigned long foo_0x80c00001000(void) { return 0x80c00001000UL; }
+
+unsigned long foo_0x81400001000(void) { return 0x81400001000UL; }
+
+unsigned long foo_0x82400001000(void) { return 0x82400001000UL; }
+
+unsigned long foo_0x84400001000(void) { return 0x84400001000UL; }
+
+unsigned long foo_0x88400001000(void) { return 0x88400001000UL; }
+
+unsigned long foo_0x90400001000(void) { return 0x90400001000UL; }
+
+unsigned long foo_0xa0400001000(void) { return 0xa0400001000UL; }
+
+unsigned long foo_0xc0400001000(void) { return 0xc0400001000UL; }
+
+unsigned long foo_0x81800001000(void) { return 0x81800001000UL; }
+
+unsigned long foo_0x82800001000(void) { return 0x82800001000UL; }
+
+unsigned long foo_0x84800001000(void) { return 0x84800001000UL; }
+
+unsigned long foo_0x88800001000(void) { return 0x88800001000UL; }
+
+unsigned long foo_0x90800001000(void) { return 0x90800001000UL; }
+
+unsigned long foo_0xa0800001000(void) { return 0xa0800001000UL; }
+
+unsigned long foo_0xc0800001000(void) { return 0xc0800001000UL; }
+
+unsigned long foo_0x83000001000(void) { return 0x83000001000UL; }
+
+unsigned long foo_0x85000001000(void) { return 0x85000001000UL; }
+
+unsigned long foo_0x89000001000(void) { return 0x89000001000UL; }
+
+unsigned long foo_0x91000001000(void) { return 0x91000001000UL; }
+
+unsigned long foo_0xa1000001000(void) { return 0xa1000001000UL; }
+
+unsigned long foo_0xc1000001000(void) { return 0xc1000001000UL; }
+
+unsigned long foo_0x86000001000(void) { return 0x86000001000UL; }
+
+unsigned long foo_0x8a000001000(void) { return 0x8a000001000UL; }
+
+unsigned long foo_0x92000001000(void) { return 0x92000001000UL; }
+
+unsigned long foo_0xa2000001000(void) { return 0xa2000001000UL; }
+
+unsigned long foo_0xc2000001000(void) { return 0xc2000001000UL; }
+
+unsigned long foo_0x8c000001000(void) { return 0x8c000001000UL; }
+
+unsigned long foo_0x94000001000(void) { return 0x94000001000UL; }
+
+unsigned long foo_0xa4000001000(void) { return 0xa4000001000UL; }
+
+unsigned long foo_0xc4000001000(void) { return 0xc4000001000UL; }
+
+unsigned long foo_0x98000001000(void) { return 0x98000001000UL; }
+
+unsigned long foo_0xa8000001000(void) { return 0xa8000001000UL; }
+
+unsigned long foo_0xc8000001000(void) { return 0xc8000001000UL; }
+
+unsigned long foo_0xb0000001000(void) { return 0xb0000001000UL; }
+
+unsigned long foo_0xd0000001000(void) { return 0xd0000001000UL; }
+
+unsigned long foo_0xe0000001000(void) { return 0xe0000001000UL; }
+
+unsigned long foo_0x100180002000(void) { return 0x100180002000UL; }
+
+unsigned long foo_0x100280002000(void) { return 0x100280002000UL; }
+
+unsigned long foo_0x100480002000(void) { return 0x100480002000UL; }
+
+unsigned long foo_0x100880002000(void) { return 0x100880002000UL; }
+
+unsigned long foo_0x101080002000(void) { return 0x101080002000UL; }
+
+unsigned long foo_0x102080002000(void) { return 0x102080002000UL; }
+
+unsigned long foo_0x104080002000(void) { return 0x104080002000UL; }
+
+unsigned long foo_0x108080002000(void) { return 0x108080002000UL; }
+
+unsigned long foo_0x110080002000(void) { return 0x110080002000UL; }
+
+unsigned long foo_0x120080002000(void) { return 0x120080002000UL; }
+
+unsigned long foo_0x180080002000(void) { return 0x180080002000UL; }
+
+unsigned long foo_0x100300002000(void) { return 0x100300002000UL; }
+
+unsigned long foo_0x100500002000(void) { return 0x100500002000UL; }
+
+unsigned long foo_0x100900002000(void) { return 0x100900002000UL; }
+
+unsigned long foo_0x101100002000(void) { return 0x101100002000UL; }
+
+unsigned long foo_0x102100002000(void) { return 0x102100002000UL; }
+
+unsigned long foo_0x104100002000(void) { return 0x104100002000UL; }
+
+unsigned long foo_0x108100002000(void) { return 0x108100002000UL; }
+
+unsigned long foo_0x110100002000(void) { return 0x110100002000UL; }
+
+unsigned long foo_0x120100002000(void) { return 0x120100002000UL; }
+
+unsigned long foo_0x140100002000(void) { return 0x140100002000UL; }
+
+unsigned long foo_0x100600002000(void) { return 0x100600002000UL; }
+
+unsigned long foo_0x100a00002000(void) { return 0x100a00002000UL; }
+
+unsigned long foo_0x101200002000(void) { return 0x101200002000UL; }
+
+unsigned long foo_0x102200002000(void) { return 0x102200002000UL; }
+
+unsigned long foo_0x104200002000(void) { return 0x104200002000UL; }
+
+unsigned long foo_0x108200002000(void) { return 0x108200002000UL; }
+
+unsigned long foo_0x110200002000(void) { return 0x110200002000UL; }
+
+unsigned long foo_0x120200002000(void) { return 0x120200002000UL; }
+
+unsigned long foo_0x140200002000(void) { return 0x140200002000UL; }
+
+unsigned long foo_0x180200002000(void) { return 0x180200002000UL; }
+
+unsigned long foo_0x100c00002000(void) { return 0x100c00002000UL; }
+
+unsigned long foo_0x101400002000(void) { return 0x101400002000UL; }
+
+unsigned long foo_0x102400002000(void) { return 0x102400002000UL; }
+
+unsigned long foo_0x104400002000(void) { return 0x104400002000UL; }
+
+unsigned long foo_0x108400002000(void) { return 0x108400002000UL; }
+
+unsigned long foo_0x110400002000(void) { return 0x110400002000UL; }
+
+unsigned long foo_0x140400002000(void) { return 0x140400002000UL; }
+
+unsigned long foo_0x180400002000(void) { return 0x180400002000UL; }
+
+unsigned long foo_0x101800002000(void) { return 0x101800002000UL; }
+
+unsigned long foo_0x102800002000(void) { return 0x102800002000UL; }
+
+unsigned long foo_0x104800002000(void) { return 0x104800002000UL; }
+
+unsigned long foo_0x108800002000(void) { return 0x108800002000UL; }
+
+unsigned long foo_0x110800002000(void) { return 0x110800002000UL; }
+
+unsigned long foo_0x120800002000(void) { return 0x120800002000UL; }
+
+unsigned long foo_0x140800002000(void) { return 0x140800002000UL; }
+
+unsigned long foo_0x180800002000(void) { return 0x180800002000UL; }
+
+unsigned long foo_0x103000002000(void) { return 0x103000002000UL; }
+
+unsigned long foo_0x105000002000(void) { return 0x105000002000UL; }
+
+unsigned long foo_0x109000002000(void) { return 0x109000002000UL; }
+
+unsigned long foo_0x111000002000(void) { return 0x111000002000UL; }
+
+unsigned long foo_0x121000002000(void) { return 0x121000002000UL; }
+
+unsigned long foo_0x141000002000(void) { return 0x141000002000UL; }
+
+unsigned long foo_0x181000002000(void) { return 0x181000002000UL; }
+
+unsigned long foo_0x106000002000(void) { return 0x106000002000UL; }
+
+unsigned long foo_0x10a000002000(void) { return 0x10a000002000UL; }
+
+unsigned long foo_0x112000002000(void) { return 0x112000002000UL; }
+
+unsigned long foo_0x122000002000(void) { return 0x122000002000UL; }
+
+unsigned long foo_0x142000002000(void) { return 0x142000002000UL; }
+
+unsigned long foo_0x182000002000(void) { return 0x182000002000UL; }
+
+unsigned long foo_0x10c000002000(void) { return 0x10c000002000UL; }
+
+unsigned long foo_0x114000002000(void) { return 0x114000002000UL; }
+
+unsigned long foo_0x124000002000(void) { return 0x124000002000UL; }
+
+unsigned long foo_0x144000002000(void) { return 0x144000002000UL; }
+
+unsigned long foo_0x184000002000(void) { return 0x184000002000UL; }
+
+unsigned long foo_0x118000002000(void) { return 0x118000002000UL; }
+
+unsigned long foo_0x128000002000(void) { return 0x128000002000UL; }
+
+unsigned long foo_0x148000002000(void) { return 0x148000002000UL; }
+
+unsigned long foo_0x188000002000(void) { return 0x188000002000UL; }
+
+unsigned long foo_0x130000002000(void) { return 0x130000002000UL; }
+
+unsigned long foo_0x150000002000(void) { return 0x150000002000UL; }
+
+unsigned long foo_0x190000002000(void) { return 0x190000002000UL; }
+
+unsigned long foo_0x160000002000(void) { return 0x160000002000UL; }
+
+unsigned long foo_0x1a0000002000(void) { return 0x1a0000002000UL; }
+
+unsigned long foo_0x1c0000002000(void) { return 0x1c0000002000UL; }