[PATCH] D135059: [NFC][AArch64] Precommit test to show missed-optimization when BFI is suboptimal to ORR with imm-shifted operand

[Mingming Liu via Phabricator via llvm-commits]

mingmingl updated this revision to Diff 468616.
mingmingl retitled this revision from "[NFC][AArch64]Precommit test to show missed-optimization when the left-shift of a bit-field positioning could be folded into ORR" to "[NFC][AArch64] Precommit test to show missed-optimization when BFI is suboptimal to ORR with imm-shifted operand".
mingmingl edited the summary of this revision.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D135059/new/

https://reviews.llvm.org/D135059

Files:
  llvm/test/CodeGen/AArch64/bitfield-insert.ll


Index: llvm/test/CodeGen/AArch64/bitfield-insert.ll
===================================================================
--- llvm/test/CodeGen/AArch64/bitfield-insert.ll
+++ llvm/test/CodeGen/AArch64/bitfield-insert.ll
@@ -285,6 +285,39 @@
   ret i32 %shl.4
 }
 
+; Optimal codegen should fold the left shift (%3) into orr.
+define i64 @test_orr_not_bfi1(i64 %0) {
+; CHECK-LABEL: test_orr_not_bfi1:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    and x8, x0, #0xff
+; CHECK-NEXT:    bfi x8, x0, #8, #8
+; CHECK-NEXT:    mov x0, x8
+; CHECK-NEXT:    ret
+  %2 = and i64 %0, 255
+  %3 = shl i64 %2, 8
+  %4 = or i64 %2, %3
+  ret i64 %4
+}
+
+; Optimal codegen is something like
+; and    x8, x23, #0x7f             -- for %2
+; ubfx   x9, x23, #8, #7            -- split %4 into (shl (and %3, 127), 7), fold shl into orr, and combine the inner and with %3 into ubfx
+; orr    x23, x8, x9, lsl #7
+define i64 @test_orr_not_bfi2(i64 %0) {
+; CHECK-LABEL: test_orr_not_bfi2:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    lsr x8, x0, #1
+; CHECK-NEXT:    and x8, x8, #0x3f80
+; CHECK-NEXT:    bfxil x8, x0, #0, #7
+; CHECK-NEXT:    mov x0, x8
+; CHECK-NEXT:    ret
+  %2 = and i64 %0, 127
+  %3 = lshr i64 %0, 1
+  %4 = and i64 %3, 16256
+  %5 = or i64 %4, %2
+  ret i64 %5
+}
+
 define void @test_nouseful_strb(i32* %ptr32, i8* %ptr8, i32 %x)  {
 ; CHECK-LABEL: test_nouseful_strb:
 ; CHECK:       // %bb.0: // %entry


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D135059.468616.patch
Type: text/x-patch
Size: 1408 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20221018/5479fe2c/attachment-0001.bin>