70904226e1
* Avoid using `CM_ScalarEpilogueNotAllowedLowTripLoop` for loops known to be predicate tail-folded, delegating to `areRuntimeChecksProfitable` to decide on the profitability of vectorizing loops with runtime checks. * Update the `areRuntimeChecksProfitable` function to consider the `ScalarEpilogueLowering` setting when assessing vectorization of a loop. With this patch, we can make more informed decisions for loops with low trip counts, especially when leveraging Profile-Guided Optimization (PGO) data.
109 lines
4.3 KiB
LLVM
109 lines
4.3 KiB
LLVM
; RUN: opt < %s -passes=loop-vectorize -mtriple aarch64-unknown-linux-gnu -mattr=+sve -prefer-predicate-over-epilogue=predicate-else-scalar-epilogue -S | FileCheck --check-prefixes=CHECK,PREDICATED %s
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; RUN: opt < %s -passes=loop-vectorize -mtriple aarch64-unknown-linux-gnu -mattr=+sve -prefer-predicate-over-epilogue=scalar-epilogue -S | FileCheck --check-prefixes=CHECK,SCALAR %s
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; This file contains the same function but with different trip-count PGO hints
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; The function is vectorized if there are no trip-count hints
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define i32 @foo_no_trip_count(ptr %a, ptr %b, ptr %c, i32 %bound) {
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; CHECK-LABEL: @foo_no_trip_count(
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; PREDICATED: vector.body
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; SCALAR: vector.body
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entry:
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br label %for.body
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for.body: ; preds = %for.body, %entry
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%idx = phi i32 [ 0, %entry ], [ %inc, %for.body ]
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%a.index = getelementptr inbounds [32 x i8], ptr %a, i32 0, i32 %idx
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%0 = load i8, ptr %a.index, align 1
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%b.index = getelementptr inbounds [32 x i8], ptr %b, i32 0, i32 %idx
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%1 = load i8, ptr %b.index, align 1
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%2 = add i8 %0, %1
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%c.index = getelementptr inbounds [32 x i8], ptr %c, i32 0, i32 %idx
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store i8 %2, ptr %c.index, align 1
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%inc = add nsw i32 %idx, 1
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%exitcond = icmp eq i32 %idx, %bound
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br i1 %exitcond, label %for.end, label %for.body
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for.end: ; preds = %for.body
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ret i32 0
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}
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; If trip-count is equal to 4, the function is not vectorised
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define i32 @foo_low_trip_count(ptr %a, ptr %b, ptr %c, i32 %bound) {
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; CHECK-LABEL: @foo_low_trip_count(
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; PREDICATED-NOT: vector.body
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; SCALAR-NOT: vector.body
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entry:
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br label %for.body
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for.body: ; preds = %for.body, %entry
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%idx = phi i32 [ 0, %entry ], [ %inc, %for.body ]
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%a.index = getelementptr inbounds [32 x i8], ptr %a, i32 0, i32 %idx
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%0 = load i8, ptr %a.index, align 1
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%b.index = getelementptr inbounds [32 x i8], ptr %b, i32 0, i32 %idx
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%1 = load i8, ptr %b.index, align 1
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%2 = add i8 %0, %1
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%c.index = getelementptr inbounds [32 x i8], ptr %c, i32 0, i32 %idx
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store i8 %2, ptr %c.index, align 1
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%inc = add nsw i32 %idx, 1
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%exitcond = icmp eq i32 %idx, %bound
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br i1 %exitcond, label %for.end, label %for.body, !prof !0
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for.end: ; preds = %for.body
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ret i32 0
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}
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; If trip-count is equal to 10, the function is vectorised when predicated tail folding is chosen
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define i32 @foo_mid_trip_count(ptr %a, ptr %b, ptr %c, i32 %bound) {
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; CHECK-LABEL: @foo_mid_trip_count(
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; PREDICATED: vector.body
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; SCALAR-NOT: vector.body
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entry:
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br label %for.body
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for.body: ; preds = %for.body, %entry
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%idx = phi i32 [ 0, %entry ], [ %inc, %for.body ]
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%a.index = getelementptr inbounds [32 x i8], ptr %a, i32 0, i32 %idx
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%0 = load i8, ptr %a.index, align 1
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%b.index = getelementptr inbounds [32 x i8], ptr %b, i32 0, i32 %idx
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%1 = load i8, ptr %b.index, align 1
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%2 = add i8 %0, %1
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%c.index = getelementptr inbounds [32 x i8], ptr %c, i32 0, i32 %idx
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store i8 %2, ptr %c.index, align 1
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%inc = add nsw i32 %idx, 1
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%exitcond = icmp eq i32 %idx, %bound
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br i1 %exitcond, label %for.end, label %for.body, !prof !1
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for.end: ; preds = %for.body
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ret i32 0
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}
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; If trip-count is equal to 40, the function is always vectorised
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define i32 @foo_high_trip_count(ptr %a, ptr %b, ptr %c, i32 %bound) {
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; CHECK-LABEL: @foo_high_trip_count(
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; PREDICATED: vector.body
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; SCALAR: vector.body
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entry:
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br label %for.body
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for.body: ; preds = %for.body, %entry
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%idx = phi i32 [ 0, %entry ], [ %inc, %for.body ]
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%a.index = getelementptr inbounds [32 x i8], ptr %a, i32 0, i32 %idx
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%0 = load i8, ptr %a.index, align 1
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%b.index = getelementptr inbounds [32 x i8], ptr %b, i32 0, i32 %idx
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%1 = load i8, ptr %b.index, align 1
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%2 = add i8 %0, %1
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%c.index = getelementptr inbounds [32 x i8], ptr %c, i32 0, i32 %idx
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store i8 %2, ptr %c.index, align 1
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%inc = add nsw i32 %idx, 1
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%exitcond = icmp eq i32 %idx, %bound
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br i1 %exitcond, label %for.end, label %for.body, !prof !2
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for.end: ; preds = %for.body
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ret i32 0
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}
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!0 = !{!"branch_weights", i32 10, i32 30}
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!1 = !{!"branch_weights", i32 10, i32 90}
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!2 = !{!"branch_weights", i32 10, i32 390}
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