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fe88774ae8
A shift and add/sub sequence combination is faster in place of a multiply by constant. Because the cycle or latency of multiply is not huge, we only consider such following worthy patterns. ``` (mul x, 2^N + 1) => (add (shl x, N), x) (mul x, -(2^N + 1)) => -(add (shl x, N), x) (mul x, 2^N - 1) => (sub (shl x, N), x) (mul x, -(2^N - 1)) => (sub x, (shl x, N)) ``` And the cycles or latency is subtarget-dependent so that we need consider the subtarget to determine to do or not do such transformation. Also data type is considered for different cycles or latency to do multiply. Differential Revision: https://reviews.llvm.org/D58950 llvm-svn: 357233
93 lines
2.6 KiB
LLVM
93 lines
2.6 KiB
LLVM
; RUN: llc -verify-machineinstrs -ppc-asm-full-reg-names -ppc-vsr-nums-as-vr -mcpu=generic < %s -mtriple=ppc64-- | FileCheck %s -check-prefix=GENERIC-CHECK
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; RUN: llc -verify-machineinstrs -ppc-asm-full-reg-names -ppc-vsr-nums-as-vr -mcpu=pwr8 < %s -mtriple=ppc64-- | FileCheck %s -check-prefixes=PWR8-CHECK,CHECK
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; RUN: llc -verify-machineinstrs -ppc-asm-full-reg-names -ppc-vsr-nums-as-vr -mcpu=pwr9 < %s -mtriple=ppc64le-- | FileCheck %s -check-prefixes=PWR9-CHECK,CHECK
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define i64 @foo(i64 %a) {
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entry:
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%mul = mul nsw i64 %a, 6
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ret i64 %mul
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}
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; GENERIC-CHECK-LABEL: @foo
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; GENERIC-CHECK: mulli r3, r3, 6
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; GENERIC-CHECK: blr
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define i64 @test1(i64 %a) {
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%tmp.1 = mul nsw i64 %a, 16 ; <i64> [#uses=1]
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ret i64 %tmp.1
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}
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; CHECK-LABEL: test1:
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; CHECK-NOT: mul
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; CHECK: sldi r[[REG1:[0-9]+]], r3, 4
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define i64 @test2(i64 %a) {
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%tmp.1 = mul nsw i64 %a, 17 ; <i64> [#uses=1]
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ret i64 %tmp.1
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}
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; CHECK-LABEL: test2:
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; CHECK-NOT: mul
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; CHECK: sldi r[[REG1:[0-9]+]], r3, 4
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; CHECK-NEXT: add r[[REG2:[0-9]+]], r3, r[[REG1]]
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define i64 @test3(i64 %a) {
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%tmp.1 = mul nsw i64 %a, 15 ; <i64> [#uses=1]
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ret i64 %tmp.1
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}
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; CHECK-LABEL: test3:
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; CHECK-NOT: mul
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; CHECK: sldi r[[REG1:[0-9]+]], r3, 4
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; CHECK-NEXT: sub r[[REG2:[0-9]+]], r[[REG1]], r3
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; negtive constant
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define i64 @test4(i64 %a) {
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%tmp.1 = mul nsw i64 %a, -16 ; <i64> [#uses=1]
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ret i64 %tmp.1
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}
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; CHECK-LABEL: test4:
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; CHECK-NOT: mul
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; CHECK: sldi r[[REG1:[0-9]+]], r3, 4
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; CHECK-NEXT: neg r[[REG2:[0-9]+]], r[[REG1]]
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define i64 @test5(i64 %a) {
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%tmp.1 = mul nsw i64 %a, -17 ; <i64> [#uses=1]
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ret i64 %tmp.1
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}
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; CHECK-LABEL: test5:
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; PWR9-CHECK: mulli r[[REG1:[0-9]+]], r3, -17
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; PWR8-CHECK-NOT: mul
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; PWR8-CHECK: sldi r[[REG1:[0-9]+]], r3, 4
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; PWR8-CHECK-NEXT: add r[[REG2:[0-9]+]], r3, r[[REG1]]
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; PWR8-CHECK-NEXT: neg r{{[0-9]+}}, r[[REG2]]
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define i64 @test6(i64 %a) {
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%tmp.1 = mul nsw i64 %a, -15 ; <i64> [#uses=1]
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ret i64 %tmp.1
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}
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; CHECK-LABEL: test6:
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; CHECK-NOT: mul
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; CHECK: sldi r[[REG1:[0-9]+]], r3, 4
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; CHECK-NEXT: sub r[[REG2:[0-9]+]], r3, r[[REG1]]
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; CHECK-NOT: neg
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; boundary case
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define i64 @test7(i64 %a) {
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%tmp.1 = mul nsw i64 %a, -9223372036854775808 ; <i64> [#uses=1]
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ret i64 %tmp.1
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}
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; CHECK-LABEL: test7:
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; CHECK-NOT: mul
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; CHECK: sldi r[[REG1:[0-9]+]], r3, 63
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define i64 @test8(i64 %a) {
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%tmp.1 = mul nsw i64 %a, 9223372036854775807 ; <i64> [#uses=1]
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ret i64 %tmp.1
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}
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; CHECK-LABEL: test8:
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; CHECK-NOT: mul
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; CHECK: sldi r[[REG1:[0-9]+]], r3, 63
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; CHECK-NEXT: sub r[[REG2:[0-9]+]], r[[REG1]], r3
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