[PATCH] D119518: [RISCV] Insert VSETVLI at the end of a basic block if we didn't produce BlockInfo.Exit.

[Craig Topper via Phabricator via llvm-commits]

This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rG541c9ba84225: [RISCV] Insert VSETVLI at the end of a basic block if we didn't produce… (authored by craig.topper).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D119518/new/

https://reviews.llvm.org/D119518

Files:
  llvm/lib/Target/RISCV/RISCVInsertVSETVLI.cpp
  llvm/test/CodeGen/RISCV/rvv/vsetvli-insert-crossbb.mir


Index: llvm/test/CodeGen/RISCV/rvv/vsetvli-insert-crossbb.mir
===================================================================
--- llvm/test/CodeGen/RISCV/rvv/vsetvli-insert-crossbb.mir
+++ llvm/test/CodeGen/RISCV/rvv/vsetvli-insert-crossbb.mir
@@ -592,12 +592,10 @@
   ; CHECK-NEXT:   [[PseudoVADD_VX_M1_:%[0-9]+]]:vr = PseudoVADD_VX_M1 [[PseudoVID_V_M1_]], [[PHI]], -1, 6, implicit $vl, implicit $vtype
   ; CHECK-NEXT:   [[MUL:%[0-9]+]]:gpr = MUL [[PHI]], [[SRLI]]
   ; CHECK-NEXT:   [[ADD:%[0-9]+]]:gpr = ADD [[COPY]], [[MUL]]
-  ; FIXME: We insert a SEW=32,LMUL=1/2 VSETVLI here but no SEW=64,LMUL=1
-  ; VSETVLI before the VADD above. This misconfigures the VADD in the case that
-  ; the loop takes its backedge.
   ; CHECK-NEXT:   dead $x0 = PseudoVSETVLIX0 killed $x0, 87, implicit-def $vl, implicit-def $vtype, implicit $vl
   ; CHECK-NEXT:   PseudoVSE32_V_MF2 killed [[PseudoVADD_VX_M1_]], killed [[ADD]], -1, 5, implicit $vl, implicit $vtype
   ; CHECK-NEXT:   [[ADDI:%[0-9]+]]:gpr = ADDI [[PHI]], 1
+  ; CHECK-NEXT:   dead $x0 = PseudoVSETVLIX0 killed $x0, 88, implicit-def $vl, implicit-def $vtype, implicit $vl
   ; CHECK-NEXT:   BLTU [[ADDI]], [[COPY1]], %bb.1
   ; CHECK-NEXT:   PseudoBR %bb.2
   ; CHECK-NEXT: {{  $}}
Index: llvm/lib/Target/RISCV/RISCVInsertVSETVLI.cpp
===================================================================
--- llvm/lib/Target/RISCV/RISCVInsertVSETVLI.cpp
+++ llvm/lib/Target/RISCV/RISCVInsertVSETVLI.cpp
@@ -334,6 +334,10 @@
     return false;
   }
 
+  bool operator!=(const VSETVLIInfo &Other) const {
+    return !(*this == Other);
+  }
+
   // Calculate the VSETVLIInfo visible to a block assuming this and Other are
   // both predecessors.
   VSETVLIInfo intersect(const VSETVLIInfo &Other) const {
@@ -1096,6 +1100,17 @@
       CurInfo = VSETVLIInfo::getUnknown();
       PrevVSETVLIMI = nullptr;
     }
+
+    // If we reach the end of the block and our current info doesn't match the
+    // expected info, insert a vsetvli to correct.
+    if (MI.isTerminator()) {
+      const VSETVLIInfo &ExitInfo = BlockInfo[MBB.getNumber()].Exit;
+      if (CurInfo.isValid() && ExitInfo.isValid() && !ExitInfo.isUnknown() &&
+          CurInfo != ExitInfo) {
+        insertVSETVLI(MBB, MI, ExitInfo, CurInfo);
+        CurInfo = ExitInfo;
+      }
+    }
   }
 }
 


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D119518.407923.patch
Type: text/x-patch
Size: 2318 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20220211/07a40090/attachment.bin>