[AArch64][SVE] Fix BRKNS bug in optimizePTestInstr

The BRKNS instruction is unlike the other instructions that set flags since it has an all active implicit predicate, so the existing PTEST(PG, BRKN(PG, A, B)) -> BRKNS(PG, A, B) in AArch64InstrInfo::optimizePTestInstr is incorrect, however PTEST(PTRUE_B(31), BRKN(PG, A, B)) -> BRKNS(PG, A, B) is correct. Spotted by @paulwalker-arm in D134946. Reviewed By: paulwalker-arm Differential Revision: https://reviews.llvm.org/D135655
llvm · Oct 12, 2022 · a17fcb2 · a17fcb2
1 parent 495d9e1
commit a17fcb2
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Showing 3 changed files with 20 additions and 3 deletions.
diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp b/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
@@ -1351,8 +1351,9 @@ bool AArch64InstrInfo::optimizePTestInstr(
       break;
     }
     case AArch64::BRKN_PPzP: {
-      auto *PredMask = MRI->getUniqueVRegDef(Pred->getOperand(1).getReg());
-      if (Mask != PredMask)
+      // PTEST(PTRUE_B(31), BRKN(PG, A, B)) -> BRKNS(PG, A, B).
+      if ((MaskOpcode != AArch64::PTRUE_B) ||
+          (Mask->getOperand(1).getImm() != 31))
         return false;
 
       NewOp = AArch64::BRKNS_PPzP;

diff --git a/llvm/lib/Target/AArch64/SVEInstrFormats.td b/llvm/lib/Target/AArch64/SVEInstrFormats.td
@@ -7987,6 +7987,7 @@ class sve_int_brkn<bit S, string asm>
 
   let Constraints = "$Pdm = $_Pdm";
   let Defs = !if(S, [NZCV], []);
+  let ElementSize = ElementSizeB;
 }
 
 multiclass sve_int_brkn<bits<1> opc, string asm, SDPatternOperator op> {

diff --git a/llvm/test/CodeGen/AArch64/sve-ptest-removal-brk.ll b/llvm/test/CodeGen/AArch64/sve-ptest-removal-brk.ll
@@ -30,7 +30,8 @@ define i32 @brkb(<vscale x 16 x i1> %pg, <vscale x 16 x i1> %a) {
 define i32 @brkn(<vscale x 16 x i1> %pg, <vscale x 16 x i1> %a, <vscale x 16 x i1> %b) {
 ; CHECK-LABEL: brkn:
 ; CHECK:       // %bb.0:
-; CHECK-NEXT:    brkns p2.b, p0/z, p1.b, p2.b
+; CHECK-NEXT:    brkn p2.b, p0/z, p1.b, p2.b
+; CHECK-NEXT:    ptest p0, p2.b
 ; CHECK-NEXT:    cset w0, ne
 ; CHECK-NEXT:    ret
   %1 = tail call <vscale x 16 x i1> @llvm.aarch64.sve.brkn.z.nxv16i1(<vscale x 16 x i1> %pg, <vscale x 16 x i1> %a, <vscale x 16 x i1> %b)
@@ -39,6 +40,19 @@ define i32 @brkn(<vscale x 16 x i1> %pg, <vscale x 16 x i1> %a, <vscale x 16 x i
   ret i32 %conv
 }
 
+define i32 @brkn_all_active(<vscale x 16 x i1> %pg, <vscale x 16 x i1> %a, <vscale x 16 x i1> %b) {
+; CHECK-LABEL: brkn_all_active:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    brkns p2.b, p0/z, p1.b, p2.b
+; CHECK-NEXT:    cset w0, ne
+; CHECK-NEXT:    ret
+  %1 = tail call <vscale x 16 x i1> @llvm.aarch64.sve.brkn.z.nxv16i1(<vscale x 16 x i1> %pg, <vscale x 16 x i1> %a, <vscale x 16 x i1> %b)
+  %2 = call <vscale x 16 x i1> @llvm.aarch64.sve.ptrue.nxv16i1(i32 31)
+  %3 = tail call i1 @llvm.aarch64.sve.ptest.any.nxv16i1(<vscale x 16 x i1> %2, <vscale x 16 x i1> %1)
+  %conv = zext i1 %3 to i32
+  ret i32 %conv
+}
+
 ; Test that ptest instruction is not removed when using a non-flag setting brk
 
 define i32 @brkpb_neg(<vscale x 16 x i1> %pg, <vscale x 16 x i1> %a, <vscale x 16 x i1> %b) {
@@ -84,3 +98,4 @@ declare <vscale x 16 x i1> @llvm.aarch64.sve.brkpb.z.nxv16i1(<vscale x 16 x i1>,
 declare <vscale x 16 x i1> @llvm.aarch64.sve.brkb.z.nxv16i1(<vscale x 16 x i1>, <vscale x 16 x i1>)
 declare <vscale x 16 x i1> @llvm.aarch64.sve.brkn.z.nxv16i1(<vscale x 16 x i1>, <vscale x 16 x i1>, <vscale x 16 x i1>)
 declare i1 @llvm.aarch64.sve.ptest.any.nxv16i1(<vscale x 16 x i1>, <vscale x 16 x i1>)
+declare <vscale x 16 x i1> @llvm.aarch64.sve.ptrue.nxv16i1(i32)