[llvm] [NVPTX] Avoid introducing unnecessary ProxyRegs and Movs in ISel (PR #120486)

[Artem Belevich via llvm-commits]

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@@ -157,38 +157,38 @@ define i16  @test_v8i8(i64 %a) {
 ; CHECK-LABEL: test_v8i8(
 ; CHECK:       {
 ; CHECK-NEXT:    .reg .b16 %rs<16>;
-; CHECK-NEXT:    .reg .b32 %r<14>;
+; CHECK-NEXT:    .reg .b32 %r<12>;
 ; CHECK-NEXT:    .reg .b64 %rd<2>;
 ; CHECK-EMPTY:
 ; CHECK-NEXT:  // %bb.0:
 ; CHECK-NEXT:    ld.param.u64 %rd1, [test_v8i8_param_0];
-; CHECK-NEXT:    cvt.u32.u64 %r1, %rd1;
-; CHECK-NEXT:    { .reg .b32 tmp; mov.b64 {tmp, %r2}, %rd1; }
-; CHECK-NEXT:    bfe.s32 %r5, %r1, 0, 8;
-; CHECK-NEXT:    cvt.s8.s32 %rs1, %r5;
-; CHECK-NEXT:    bfe.s32 %r6, %r1, 8, 8;
-; CHECK-NEXT:    cvt.s8.s32 %rs2, %r6;
-; CHECK-NEXT:    bfe.s32 %r7, %r1, 16, 8;
-; CHECK-NEXT:    cvt.s8.s32 %rs3, %r7;
-; CHECK-NEXT:    bfe.s32 %r8, %r1, 24, 8;
-; CHECK-NEXT:    cvt.s8.s32 %rs4, %r8;
-; CHECK-NEXT:    bfe.s32 %r9, %r2, 0, 8;
-; CHECK-NEXT:    cvt.s8.s32 %rs5, %r9;
-; CHECK-NEXT:    bfe.s32 %r10, %r2, 8, 8;
-; CHECK-NEXT:    cvt.s8.s32 %rs6, %r10;
-; CHECK-NEXT:    bfe.s32 %r11, %r2, 16, 8;
-; CHECK-NEXT:    cvt.s8.s32 %rs7, %r11;
-; CHECK-NEXT:    bfe.s32 %r12, %r2, 24, 8;
-; CHECK-NEXT:    cvt.s8.s32 %rs8, %r12;
+; CHECK-NEXT:    { .reg .b32 tmp; mov.b64 {tmp, %r1}, %rd1; }
+; CHECK-NEXT:    cvt.u32.u64 %r2, %rd1;
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Artem-B wrote:

Future improvement opportunity: Coalesce partial mov and cvt into `mov.b64 {%r2, %r1}, %rd1`.

https://github.com/llvm/llvm-project/pull/120486