[Matrix] Skip already fused instructions before trying to fuse multiply.

lowerDotProduct called above may already lower a matrix multiply and
mark it as procssed by adding it to FusedInsts. Don't try to process it
again in LowerMatrixMultiplyFused by checking if FusedInsts.

Without this change, we trigger an assertion when trying to erase the
same original matrix multiply twice.

Author: fhahn

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();
 

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)