[llvm] 8e4b089 - [LoongArch] Return true from shouldConsiderGEPOffsetSplit (#88371)

[via llvm-commits]

Author: wanglei
Date: 2024-04-15T09:01:04+08:00
New Revision: 8e4b0890a61088ae55b4bccbb59e5c5e10d28385

URL: https://github.com/llvm/llvm-project/commit/8e4b0890a61088ae55b4bccbb59e5c5e10d28385
DIFF: https://github.com/llvm/llvm-project/commit/8e4b0890a61088ae55b4bccbb59e5c5e10d28385.diff

LOG: [LoongArch] Return true from shouldConsiderGEPOffsetSplit (#88371)

If not performing gep splits can prevent important optimizations, such
as preventing the element indices / member offsets from being         
(partially) folded into load/store instruction immediates.

Added: 
    

Modified: 
    llvm/lib/Target/LoongArch/LoongArchISelLowering.h
    llvm/test/Transforms/CodeGenPrepare/LoongArch/splitgep.ll

Removed: 
    


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diff  --git a/llvm/lib/Target/LoongArch/LoongArchISelLowering.h b/llvm/lib/Target/LoongArch/LoongArchISelLowering.h
index 9e9ac0b8269291..4bb6c049f8d758 100644
--- a/llvm/lib/Target/LoongArch/LoongArchISelLowering.h
+++ b/llvm/lib/Target/LoongArch/LoongArchISelLowering.h
@@ -238,6 +238,7 @@ class LoongArchTargetLowering : public TargetLowering {
   bool isShuffleMaskLegal(ArrayRef<int> Mask, EVT VT) const override {
     return false;
   }
+  bool shouldConsiderGEPOffsetSplit() const override { return true; }
 
 private:
   /// Target-specific function used to lower LoongArch calling conventions.

diff  --git a/llvm/test/Transforms/CodeGenPrepare/LoongArch/splitgep.ll b/llvm/test/Transforms/CodeGenPrepare/LoongArch/splitgep.ll
index ca2a16a0ca7ecd..20cc25e95adf97 100644
--- a/llvm/test/Transforms/CodeGenPrepare/LoongArch/splitgep.ll
+++ b/llvm/test/Transforms/CodeGenPrepare/LoongArch/splitgep.ll
@@ -4,9 +4,9 @@
 define void @test(ptr %sp, ptr %t, i32 %n) {
 ; CHECK-LABEL: @test(
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    %s = load ptr, ptr %sp, align 8
-; CHECK-NEXT:    br label %while_cond
-
+; CHECK-NEXT:    %splitgep1 = getelementptr i8, ptr %t, i64 80000
+; CHECK-NEXT:    %s = load ptr, ptr %sp
+; CHECK-NEXT:    %splitgep = getelementptr i8, ptr %s, i64 80000
 entry:
   %s = load ptr, ptr %sp
   br label %while_cond