606d25e545
When rewriting the call sites to call the new specialised functions, a
single call site can be matched by two different specialisations - a
"less specialised" version of the function and a "more specialised"
version of the function, e.g. for a function
void f(int x, int y)
the call like `f(1, 2)` could be matched by either
void f.1(int x /* int y == 2 */);
or
void f.2(/* int x == 1, int y == 2 */);
The `FunctionSpecialisation` pass tries to match specialisation in the
order of decreasing gain, so "more specialised" functions are
preferred to "less specialised" functions. This breaks, however, when
using the flag `-force-function-specialization`, in which case the
cost/benefit analysis is not performed and all the specialisations are
equally preferable.
This patch makes the pass calculate specialisation gain and order the
specialisations accordingly even when `-force-function-specialization`
is used, under the assumption that this flag has purely debugging
purpose and it is reasonable to ignore the extra computing effort it
incurs.
Reviewed By: ChuanqiXu, labrinea
Differential Revision: https://reviews.llvm.org/D136180
59 lines
1.5 KiB
LLVM
59 lines
1.5 KiB
LLVM
; RUN: opt -S --passes=function-specialization,deadargelim -force-function-specialization < %s | FileCheck %s
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define dso_local i32 @add(i32 %x, i32 %y) {
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entry:
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%add = add nsw i32 %y, %x
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ret i32 %add
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}
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define dso_local i32 @sub(i32 %x, i32 %y) {
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entry:
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%sub = sub nsw i32 %x, %y
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ret i32 %sub
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}
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define internal i32 @f(i32 %x, i32 %y, ptr %u, ptr %v) noinline {
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entry:
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%call = tail call i32 %u(i32 %x, i32 %y)
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%call1 = tail call i32 %v(i32 %x, i32 %y)
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%mul = mul nsw i32 %call1, %call
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ret i32 %mul
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}
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define dso_local i32 @g0(i32 %x, i32 %y) {
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; CHECK-LABEL: @g0
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; CHECK: call i32 @f.2(i32 [[X:%.*]], i32 [[Y:%.*]])
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entry:
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%call = tail call i32 @f(i32 %x, i32 %y, ptr @add, ptr @add)
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ret i32 %call
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}
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define dso_local i32 @g1(i32 %x, i32 %y) {
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; CHECK-LABEL: @g1(
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; CHECK: call i32 @f.1(i32 [[X:%.*]], i32 [[Y:%.*]])
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entry:
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%call = tail call i32 @f(i32 %x, i32 %y, ptr @sub, ptr @add)
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ret i32 %call
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}
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define dso_local i32 @g2(i32 %x, i32 %y, ptr %v) {
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; CHECK-LABEL @g2
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; CHECK call i32 @f.3(i32 [[X:%.*]], i32 [[Y:%.*]], ptr [[V:%.*]])
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entry:
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%call = tail call i32 @f(i32 %x, i32 %y, ptr @sub, ptr %v)
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ret i32 %call
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}
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; CHECK-LABEL: define {{.*}} i32 @f.1
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; CHECK: call i32 @sub(i32 %x, i32 %y)
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; CHECK-NEXT: call i32 @add(i32 %x, i32 %y)
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; CHECK-LABEL: define {{.*}} i32 @f.2
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; CHECK: call i32 @add(i32 %x, i32 %y)
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; CHECK-NEXT call i32 @add(i32 %x, i32 %y)
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; CHECK-LABEL: define {{.*}} i32 @f.3
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; CHECK: call i32 @sub(i32 %x, i32 %y)
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; CHECK-NEXT: call i32 %v(i32 %x, i32 %y)
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