[AMDGPU] - Add bitreplicate const folding tests (#72649)

Add more test cases for `s_bitreplicate` constant folding.

Author: OutOfCache

llvm/test/CodeGen/AMDGPU/llvm.amdgcn.bitreplicate.ll

@@ -16,6 +16,52 @@ entry:
   ret i64 %br
 }
 
+define i64 @test_s_bitreplicate_constant_zero() {
+; GFX11-LABEL: test_s_bitreplicate_constant_zero:
+; GFX11:       ; %bb.0: ; %entry
+; GFX11-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
+; GFX11-NEXT:    v_dual_mov_b32 v0, 0 :: v_dual_mov_b32 v1, 0
+; GFX11-NEXT:    s_setpc_b64 s[30:31]
+entry:
+  %br = call i64 @llvm.amdgcn.s.bitreplicate(i32 0)
+  ret i64 %br
+}
+
+define i64 @test_s_bitreplicate_constant_neg_one() {
+; GFX11-LABEL: test_s_bitreplicate_constant_neg_one:
+; GFX11:       ; %bb.0: ; %entry
+; GFX11-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
+; GFX11-NEXT:    v_dual_mov_b32 v0, -1 :: v_dual_mov_b32 v1, -1
+; GFX11-NEXT:    s_setpc_b64 s[30:31]
+entry:
+  %br = call i64 @llvm.amdgcn.s.bitreplicate(i32 -1)
+  ret i64 %br
+}
+
+define i64 @test_s_bitreplicate_constant_undef() {
+; GFX11-LABEL: test_s_bitreplicate_constant_undef:
+; GFX11:       ; %bb.0: ; %entry
+; GFX11-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
+; GFX11-NEXT:    s_bitreplicate_b64_b32 s[0:1], s0
+; GFX11-NEXT:    v_dual_mov_b32 v0, s0 :: v_dual_mov_b32 v1, s1
+; GFX11-NEXT:    s_setpc_b64 s[30:31]
+entry:
+  %br = call i64 @llvm.amdgcn.s.bitreplicate(i32 undef)
+  ret i64 %br
+}
+
+define i64 @test_s_bitreplicate_constant_poison() {
+; GFX11-LABEL: test_s_bitreplicate_constant_poison:
+; GFX11:       ; %bb.0: ; %entry
+; GFX11-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
+; GFX11-NEXT:    s_bitreplicate_b64_b32 s[0:1], s0
+; GFX11-NEXT:    v_dual_mov_b32 v0, s0 :: v_dual_mov_b32 v1, s1
+; GFX11-NEXT:    s_setpc_b64 s[30:31]
+entry:
+  %br = call i64 @llvm.amdgcn.s.bitreplicate(i32 poison)
+  ret i64 %br
+}
+
 define amdgpu_cs void @test_s_bitreplicate_sgpr(i32 inreg %mask, ptr addrspace(1) %out) {
 ; GFX11-LABEL: test_s_bitreplicate_sgpr:
 ; GFX11:       ; %bb.0: ; %entry