[llvm] [SPARC] Emit a TRUNCATE when combining truncating BSWAP-STOREs (PR #210483)

[Sergei Barannikov via llvm-commits]

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@@ -667,4 +801,149 @@ define void @u64_bswapstore_misaligned(ptr %0, i64 %1) #0 {
   ret void
 }
 
+define void @u16_bswapstore_extended(ptr %0, i16 %1) #0 {
+; SPARC32-LABEL: u16_bswapstore_extended:
+; SPARC32:       ! %bb.0:
+; SPARC32-NEXT:    add %sp, -96, %sp
+; SPARC32-NEXT:    add %sp, 92, %o2
+; SPARC32-NEXT:    sta %o1, [%o2] #ASI_P_L
+; SPARC32-NEXT:    lduh [%sp+92], %o1
+; SPARC32-NEXT:    st %o1, [%o0]
+; SPARC32-NEXT:    retl
+; SPARC32-NEXT:    add %sp, 96, %sp
+;
+; SPARCEL-LABEL: u16_bswapstore_extended:
+; SPARCEL:       ! %bb.0:
+; SPARCEL-NEXT:    add %sp, -96, %sp
+; SPARCEL-NEXT:    add %sp, 92, %o2
+; SPARCEL-NEXT:    sta %o1, [%o2] #ASI_P
+; SPARCEL-NEXT:    or %o2, 2, %o1
+; SPARCEL-NEXT:    lduh [%o1], %o1
+; SPARCEL-NEXT:    st %o1, [%o0]
+; SPARCEL-NEXT:    retl
+; SPARCEL-NEXT:    add %sp, 96, %sp
+;
+; SPARC64-LABEL: u16_bswapstore_extended:
+; SPARC64:       ! %bb.0:
+; SPARC64-NEXT:    add %sp, -144, %sp
+; SPARC64-NEXT:    add %sp, 2187, %o2
+; SPARC64-NEXT:    sta %o1, [%o2] #ASI_P_L
+; SPARC64-NEXT:    lduh [%sp+2187], %o1
+; SPARC64-NEXT:    st %o1, [%o0]
+; SPARC64-NEXT:    retl
+; SPARC64-NEXT:    add %sp, 144, %sp
+  %3 = tail call i16 @llvm.bswap.i16(i16 %1)
+  %4 = zext i16 %3 to i32
+  store i32 %4, ptr %0, align 4
+  ret void
+}
+
+define void @u32_bswapstore_extended(ptr %0, i32 %1) #0 {
+; SPARC32-LABEL: u32_bswapstore_extended:
+; SPARC32:       ! %bb.0:
+; SPARC32-NEXT:    add %sp, -96, %sp
+; SPARC32-NEXT:    add %sp, 92, %o2
+; SPARC32-NEXT:    sta %o1, [%o2] #ASI_P_L
+; SPARC32-NEXT:    ld [%sp+92], %o3
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s-barannikov wrote:

I'm probably missing something, why is %o3 unused?..

https://github.com/llvm/llvm-project/pull/210483