[llvm-branch-commits] [llvm] release/19.x: [Matrix] Skip already fused instructions before trying to fuse multiply. (PR #118020)

[via llvm-branch-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-transforms

Author: None (llvmbot)

<details>
<summary>Changes</summary>

Backport 12cefcc7ecd2615069206b35b0ea81b9e78bb1ea

Requested by: @<!-- -->fhahn

---
Full diff: https://github.com/llvm/llvm-project/pull/118020.diff


2 Files Affected:

- (modified) llvm/lib/Transforms/Scalar/LowerMatrixIntrinsics.cpp (+2-1) 
- (added) llvm/test/Transforms/LowerMatrixIntrinsics/dot-product-int-also-fusable-multiply.ll (+49) 


``````````diff
diff --git a/llvm/lib/Transforms/Scalar/LowerMatrixIntrinsics.cpp b/llvm/lib/Transforms/Scalar/LowerMatrixIntrinsics.cpp
index 6a681fd9339717..a44a123fdf8cda 100644
--- a/llvm/lib/Transforms/Scalar/LowerMatrixIntrinsics.cpp
+++ b/llvm/lib/Transforms/Scalar/LowerMatrixIntrinsics.cpp
@@ -1014,7 +1014,8 @@ class LowerMatrixIntrinsics {
 
     // Third, try to fuse candidates.
     for (CallInst *CI : MaybeFusableInsts)
-      LowerMatrixMultiplyFused(CI, FusedInsts, LifetimeEnds);
+      if (!FusedInsts.contains(CI))
+        LowerMatrixMultiplyFused(CI, FusedInsts, LifetimeEnds);
 
     Changed = !FusedInsts.empty();
 
diff --git a/llvm/test/Transforms/LowerMatrixIntrinsics/dot-product-int-also-fusable-multiply.ll b/llvm/test/Transforms/LowerMatrixIntrinsics/dot-product-int-also-fusable-multiply.ll
new file mode 100644
index 00000000000000..b78d56646d9e4d
--- /dev/null
+++ b/llvm/test/Transforms/LowerMatrixIntrinsics/dot-product-int-also-fusable-multiply.ll
@@ -0,0 +1,49 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -p lower-matrix-intrinsics -S %s | FileCheck %s
+
+define void @test(ptr %p, <8 x i32> %x) {
+; CHECK-LABEL: define void @test(
+; CHECK-SAME: ptr [[P:%.*]], <8 x i32> [[X:%.*]]) {
+; CHECK-NEXT:    [[L:%.*]] = load <8 x i32>, ptr [[P]], align 4
+; CHECK-NEXT:    [[SPLIT:%.*]] = shufflevector <8 x i32> [[X]], <8 x i32> poison, <1 x i32> zeroinitializer
+; CHECK-NEXT:    [[SPLIT1:%.*]] = shufflevector <8 x i32> [[X]], <8 x i32> poison, <1 x i32> <i32 1>
+; CHECK-NEXT:    [[SPLIT2:%.*]] = shufflevector <8 x i32> [[X]], <8 x i32> poison, <1 x i32> <i32 2>
+; CHECK-NEXT:    [[SPLIT3:%.*]] = shufflevector <8 x i32> [[X]], <8 x i32> poison, <1 x i32> <i32 3>
+; CHECK-NEXT:    [[SPLIT4:%.*]] = shufflevector <8 x i32> [[X]], <8 x i32> poison, <1 x i32> <i32 4>
+; CHECK-NEXT:    [[SPLIT5:%.*]] = shufflevector <8 x i32> [[X]], <8 x i32> poison, <1 x i32> <i32 5>
+; CHECK-NEXT:    [[SPLIT6:%.*]] = shufflevector <8 x i32> [[X]], <8 x i32> poison, <1 x i32> <i32 6>
+; CHECK-NEXT:    [[SPLIT7:%.*]] = shufflevector <8 x i32> [[X]], <8 x i32> poison, <1 x i32> <i32 7>
+; CHECK-NEXT:    [[TMP1:%.*]] = extractelement <1 x i32> [[SPLIT]], i64 0
+; CHECK-NEXT:    [[TMP2:%.*]] = insertelement <8 x i32> poison, i32 [[TMP1]], i64 0
+; CHECK-NEXT:    [[TMP3:%.*]] = extractelement <1 x i32> [[SPLIT1]], i64 0
+; CHECK-NEXT:    [[TMP4:%.*]] = insertelement <8 x i32> [[TMP2]], i32 [[TMP3]], i64 1
+; CHECK-NEXT:    [[TMP5:%.*]] = extractelement <1 x i32> [[SPLIT2]], i64 0
+; CHECK-NEXT:    [[TMP6:%.*]] = insertelement <8 x i32> [[TMP4]], i32 [[TMP5]], i64 2
+; CHECK-NEXT:    [[TMP7:%.*]] = extractelement <1 x i32> [[SPLIT3]], i64 0
+; CHECK-NEXT:    [[TMP8:%.*]] = insertelement <8 x i32> [[TMP6]], i32 [[TMP7]], i64 3
+; CHECK-NEXT:    [[TMP9:%.*]] = extractelement <1 x i32> [[SPLIT4]], i64 0
+; CHECK-NEXT:    [[TMP10:%.*]] = insertelement <8 x i32> [[TMP8]], i32 [[TMP9]], i64 4
+; CHECK-NEXT:    [[TMP11:%.*]] = extractelement <1 x i32> [[SPLIT5]], i64 0
+; CHECK-NEXT:    [[TMP12:%.*]] = insertelement <8 x i32> [[TMP10]], i32 [[TMP11]], i64 5
+; CHECK-NEXT:    [[TMP13:%.*]] = extractelement <1 x i32> [[SPLIT6]], i64 0
+; CHECK-NEXT:    [[TMP14:%.*]] = insertelement <8 x i32> [[TMP12]], i32 [[TMP13]], i64 6
+; CHECK-NEXT:    [[TMP15:%.*]] = extractelement <1 x i32> [[SPLIT7]], i64 0
+; CHECK-NEXT:    [[TMP16:%.*]] = insertelement <8 x i32> [[TMP14]], i32 [[TMP15]], i64 7
+; CHECK-NEXT:    [[TMP17:%.*]] = mul <8 x i32> [[L]], [[TMP16]]
+; CHECK-NEXT:    [[TMP18:%.*]] = call i32 @llvm.vector.reduce.add.v8i32(<8 x i32> [[TMP17]])
+; CHECK-NEXT:    [[TMP19:%.*]] = insertelement <1 x i32> poison, i32 [[TMP18]], i64 0
+; CHECK-NEXT:    [[E:%.*]] = extractelement <1 x i32> [[TMP19]], i64 0
+; CHECK-NEXT:    store i32 [[E]], ptr [[P]], align 4
+; CHECK-NEXT:    ret void
+;
+  %l = load <8 x i32>, ptr %p, align 4
+  %t = tail call <8 x i32> @llvm.matrix.transpose.v8i32(<8 x i32> %x, i32 1, i32 8)
+  %m = tail call <1 x i32> @llvm.matrix.multiply.v1i32.v8i32.v8i32(<8 x i32> %l, <8 x i32> %t, i32 1, i32 8, i32 1)
+  %e = extractelement <1 x i32> %m, i64 0
+  store i32 %e, ptr %p, align 4
+  ret void
+}
+
+declare <8 x i32> @llvm.matrix.transpose.v8i32(<8 x i32>, i32 immarg, i32 immarg)
+
+declare <1 x i32> @llvm.matrix.multiply.v1i32.v8i32.v8i32(<8 x i32>, <8 x i32>, i32 immarg, i32 immarg, i32 immarg)

``````````

</details>


https://github.com/llvm/llvm-project/pull/118020