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[InstCombine] allow fmul fold with less than 'fast' 

llvm-svn: 326502
This commit is contained in:
Sanjay Patel 2018-03-01 22:53:47 +00:00
parent 40388bdfb9
commit 7373ae5c9a
2 changed files with 14 additions and 12 deletions
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2
llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
View File

@ -676,7 +676,7 @@ Instruction *InstCombiner::visitFMul(BinaryOperator &I) {
// latency of the instruction Y is amortized by the expression of X*X,
// and therefore Y is in a "less critical" position compared to what it
// was before the transformation.
if (I.isFast()) {
if (I.hasAllowReassoc()) {
if (match(Op0, m_OneUse(m_c_FMul(m_Specific(Op1), m_Value(Y)))) &&
Op1 != Y) {
Value *XX = Builder.CreateFMulFMF(Op1, Op1, &I);

24
llvm/test/Transforms/InstCombine/fmul.ll
View File

@ -228,15 +228,17 @@ define float @fabs_x_fabs(float %x, float %y) {
}
; (X*Y) * X => (X*X) * Y
; The transform only requires 'reassoc', but test other FMF in
; the commuted variants to make sure FMF propagates as expected.
define float @reassoc_common_operand1(float %x, float %y) {
; CHECK-LABEL: @reassoc_common_operand1(
; CHECK-NEXT: [[TMP1:%.*]] = fmul fast float [[X:%.*]], [[X]]
; CHECK-NEXT: [[MUL2:%.*]] = fmul fast float [[TMP1]], [[Y:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = fmul reassoc float [[X:%.*]], [[X]]
; CHECK-NEXT: [[MUL2:%.*]] = fmul reassoc float [[TMP1]], [[Y:%.*]]
; CHECK-NEXT: ret float [[MUL2]]
;
%mul1 = fmul float %x, %y
%mul2 = fmul fast float %mul1, %x
%mul2 = fmul reassoc float %mul1, %x
ret float %mul2
}
@ -258,13 +260,13 @@ define float @reassoc_common_operand2(float %x, float %y) {
define float @reassoc_common_operand3(float %x1, float %y) {
; CHECK-LABEL: @reassoc_common_operand3(
; CHECK-NEXT: [[X:%.*]] = fdiv float [[X1:%.*]], 3.000000e+00
; CHECK-NEXT: [[TMP1:%.*]] = fmul fast float [[X]], [[X]]
; CHECK-NEXT: [[MUL2:%.*]] = fmul fast float [[TMP1]], [[Y:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = fmul reassoc nnan float [[X]], [[X]]
; CHECK-NEXT: [[MUL2:%.*]] = fmul reassoc nnan float [[TMP1]], [[Y:%.*]]
; CHECK-NEXT: ret float [[MUL2]]
;
%x = fdiv float %x1, 3.0 ; thwart complexity-based canonicalization
%mul1 = fmul float %x, %y
%mul2 = fmul fast float %x, %mul1
%mul2 = fmul reassoc nnan float %x, %mul1
ret float %mul2
}
@ -273,13 +275,13 @@ define float @reassoc_common_operand3(float %x1, float %y) {
define float @reassoc_common_operand4(float %x1, float %y) {
; CHECK-LABEL: @reassoc_common_operand4(
; CHECK-NEXT: [[X:%.*]] = fdiv float [[X1:%.*]], 3.000000e+00
; CHECK-NEXT: [[TMP1:%.*]] = fmul fast float [[X]], [[X]]
; CHECK-NEXT: [[MUL2:%.*]] = fmul fast float [[TMP1]], [[Y:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = fmul reassoc ninf float [[X]], [[X]]
; CHECK-NEXT: [[MUL2:%.*]] = fmul reassoc ninf float [[TMP1]], [[Y:%.*]]
; CHECK-NEXT: ret float [[MUL2]]
;
%x = fdiv float %x1, 3.0 ; thwart complexity-based canonicalization
%mul1 = fmul float %y, %x
%mul2 = fmul fast float %x, %mul1
%mul2 = fmul reassoc ninf float %x, %mul1
ret float %mul2
}
@ -288,12 +290,12 @@ define float @reassoc_common_operand4(float %x1, float %y) {
define float @reassoc_common_operand_multi_use(float %x, float %y) {
; CHECK-LABEL: @reassoc_common_operand_multi_use(
; CHECK-NEXT: [[MUL1:%.*]] = fmul float [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: [[MUL2:%.*]] = fmul fast float [[MUL1]], [[X]]
; CHECK-NEXT: [[MUL2:%.*]] = fmul reassoc float [[MUL1]], [[X]]
; CHECK-NEXT: call void @use_f32(float [[MUL1]])
; CHECK-NEXT: ret float [[MUL2]]
;
%mul1 = fmul float %x, %y
%mul2 = fmul fast float %mul1, %x
%mul2 = fmul reassoc float %mul1, %x
call void @use_f32(float %mul1)
ret float %mul2
}