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587c136c31
elements to minimize the number of multiplies required to compute the final result. This uses a heuristic to attempt to form near-optimal binary exponentiation-style multiply chains. While there are some cases it misses, it seems to at least a decent job on a very diverse range of inputs. Initial benchmarks show no interesting regressions, and an 8% improvement on SPASS. Let me know if any other interesting results (in either direction) crop up! Credit to Richard Smith for the core algorithm, and helping code the patch itself. llvm-svn: 155616
135 lines
2.2 KiB
LLVM
135 lines
2.2 KiB
LLVM
; RUN: opt < %s -reassociate -S | FileCheck %s
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define i32 @test1(i32 %a, i32 %b) {
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; CHECK: @test1
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; CHECK: mul i32 %a, %a
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; CHECK-NEXT: mul i32 %a, 2
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; CHECK-NEXT: add
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; CHECK-NEXT: mul
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; CHECK-NEXT: add
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; CHECK-NEXT: ret
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entry:
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%tmp.2 = mul i32 %a, %a
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%tmp.5 = shl i32 %a, 1
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%tmp.6 = mul i32 %tmp.5, %b
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%tmp.10 = mul i32 %b, %b
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%tmp.7 = add i32 %tmp.6, %tmp.2
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%tmp.11 = add i32 %tmp.7, %tmp.10
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ret i32 %tmp.11
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}
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define i32 @test2(i32 %t) {
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; CHECK: @test2
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; CHECK: mul
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; CHECK-NEXT: add
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; CHECK-NEXT: ret
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entry:
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%a = mul i32 %t, 6
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%b = mul i32 %t, 36
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%c = add i32 %b, 15
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%d = add i32 %c, %a
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ret i32 %d
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}
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define i32 @test3(i32 %x) {
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; (x^8)
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; CHECK: @test3
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; CHECK: mul
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; CHECK-NEXT: mul
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; CHECK-NEXT: mul
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; CHECK-NEXT: ret
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entry:
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%a = mul i32 %x, %x
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%b = mul i32 %a, %x
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%c = mul i32 %b, %x
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%d = mul i32 %c, %x
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%e = mul i32 %d, %x
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%f = mul i32 %e, %x
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%g = mul i32 %f, %x
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ret i32 %g
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}
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define i32 @test4(i32 %x) {
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; (x^7)
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; CHECK: @test4
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; CHECK: mul
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; CHECK-NEXT: mul
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; CHECK-NEXT: mul
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; CHECK-NEXT: mul
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; CHECK-NEXT: ret
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entry:
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%a = mul i32 %x, %x
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%b = mul i32 %a, %x
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%c = mul i32 %b, %x
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%d = mul i32 %c, %x
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%e = mul i32 %d, %x
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%f = mul i32 %e, %x
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ret i32 %f
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}
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define i32 @test5(i32 %x, i32 %y) {
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; (x^4) * (y^2)
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; CHECK: @test5
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; CHECK: mul
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; CHECK-NEXT: mul
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; CHECK-NEXT: mul
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; CHECK-NEXT: ret
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entry:
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%a = mul i32 %x, %y
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%b = mul i32 %a, %y
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%c = mul i32 %b, %x
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%d = mul i32 %c, %x
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%e = mul i32 %d, %x
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ret i32 %e
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}
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define i32 @test6(i32 %x, i32 %y, i32 %z) {
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; (x^5) * (y^3) * z
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; CHECK: @test6
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; CHECK: mul
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; CHECK-NEXT: mul
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; CHECK-NEXT: mul
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; CHECK-NEXT: mul
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; CHECK-NEXT: mul
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; CHECK-NEXT: mul
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; CHECK-NEXT: ret
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entry:
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%a = mul i32 %x, %y
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%b = mul i32 %a, %x
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%c = mul i32 %b, %y
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%d = mul i32 %c, %x
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%e = mul i32 %d, %y
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%f = mul i32 %e, %x
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%g = mul i32 %f, %z
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%h = mul i32 %g, %x
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ret i32 %h
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}
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define i32 @test7(i32 %x, i32 %y, i32 %z) {
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; (x^4) * (y^3) * (z^2)
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; CHECK: @test7
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; CHECK: mul
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; CHECK-NEXT: mul
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; CHECK-NEXT: mul
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; CHECK-NEXT: mul
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; CHECK-NEXT: mul
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; CHECK-NEXT: ret
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entry:
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%a = mul i32 %y, %x
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%b = mul i32 %a, %z
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%c = mul i32 %b, %z
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%d = mul i32 %c, %x
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%e = mul i32 %d, %y
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%f = mul i32 %e, %y
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%g = mul i32 %f, %x
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%h = mul i32 %g, %x
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ret i32 %h
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}
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