[llvm] r222705 - Bug 21610: Canonicalize min/max fcmp selects to use ordered comparisons
Matt Arsenault
Matthew.Arsenault at amd.com
Mon Nov 24 15:15:18 PST 2014
Author: arsenm
Date: Mon Nov 24 17:15:18 2014
New Revision: 222705
URL: http://llvm.org/viewvc/llvm-project?rev=222705&view=rev
Log:
Bug 21610: Canonicalize min/max fcmp selects to use ordered comparisons
Added:
llvm/trunk/test/Transforms/InstCombine/unordered-fcmp-select.ll
Modified:
llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp
llvm/trunk/test/Transforms/LoopVectorize/minmax_reduction.ll
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp?rev=222705&r1=222704&r2=222705&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp Mon Nov 24 17:15:18 2014
@@ -928,8 +928,22 @@ Instruction *InstCombiner::visitSelectIn
!CFPf->getValueAPF().isZero()))
return ReplaceInstUsesWith(SI, TrueVal);
}
- // NOTE: if we wanted to, this is where to detect MIN/MAX
+ // Canonicalize to use ordered comparisons by swapping the select
+ // operands.
+ //
+ // e.g.
+ // (X ugt Y) ? X : Y -> (X ole Y) ? Y : X
+ if (FCI->hasOneUse() && FCmpInst::isUnordered(FCI->getPredicate())) {
+ FCmpInst::Predicate InvPred = FCI->getInversePredicate();
+ Value *NewCond = Builder->CreateFCmp(InvPred, TrueVal, FalseVal,
+ FCI->getName() + ".inv");
+
+ return SelectInst::Create(NewCond, FalseVal, TrueVal,
+ SI.getName() + ".p");
+ }
+
+ // NOTE: if we wanted to, this is where to detect MIN/MAX
} else if (FCI->getOperand(0) == FalseVal && FCI->getOperand(1) == TrueVal){
// Transform (X == Y) ? Y : X -> X
if (FCI->getPredicate() == FCmpInst::FCMP_OEQ) {
@@ -955,6 +969,21 @@ Instruction *InstCombiner::visitSelectIn
!CFPf->getValueAPF().isZero()))
return ReplaceInstUsesWith(SI, TrueVal);
}
+
+ // Canonicalize to use ordered comparisons by swapping the select
+ // operands.
+ //
+ // e.g.
+ // (X ugt Y) ? X : Y -> (X ole Y) ? X : Y
+ if (FCI->hasOneUse() && FCmpInst::isUnordered(FCI->getPredicate())) {
+ FCmpInst::Predicate InvPred = FCI->getInversePredicate();
+ Value *NewCond = Builder->CreateFCmp(InvPred, FalseVal, TrueVal,
+ FCI->getName() + ".inv");
+
+ return SelectInst::Create(NewCond, FalseVal, TrueVal,
+ SI.getName() + ".p");
+ }
+
// NOTE: if we wanted to, this is where to detect MIN/MAX
}
// NOTE: if we wanted to, this is where to detect ABS
Added: llvm/trunk/test/Transforms/InstCombine/unordered-fcmp-select.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/unordered-fcmp-select.ll?rev=222705&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/unordered-fcmp-select.ll (added)
+++ llvm/trunk/test/Transforms/InstCombine/unordered-fcmp-select.ll Mon Nov 24 17:15:18 2014
@@ -0,0 +1,125 @@
+; RUN: opt -S -instcombine < %s | FileCheck %s
+
+; CHECK-LABEL: @select_max_ugt(
+; CHECK: %cmp.inv = fcmp ole float %a, %b
+; CHECK-NEXT: %sel = select i1 %cmp.inv, float %b, float %a
+; CHECK-NEXT: ret float %sel
+define float @select_max_ugt(float %a, float %b) {
+ %cmp = fcmp ugt float %a, %b
+ %sel = select i1 %cmp, float %a, float %b
+ ret float %sel
+}
+
+; CHECK-LABEL: @select_max_uge(
+; CHECK: %cmp.inv = fcmp olt float %a, %b
+; CHECK-NEXT: %sel = select i1 %cmp.inv, float %b, float %a
+; CHECK-NEXT: ret float %sel
+define float @select_max_uge(float %a, float %b) {
+ %cmp = fcmp uge float %a, %b
+ %sel = select i1 %cmp, float %a, float %b
+ ret float %sel
+}
+
+; CHECK-LABEL: @select_min_ugt(
+; CHECK: %cmp.inv = fcmp ole float %a, %b
+; CHECK-NEXT: %sel = select i1 %cmp.inv, float %a, float %b
+; CHECK-NEXT: ret float %sel
+define float @select_min_ugt(float %a, float %b) {
+ %cmp = fcmp ugt float %a, %b
+ %sel = select i1 %cmp, float %b, float %a
+ ret float %sel
+}
+
+; CHECK-LABEL: @select_min_uge(
+; CHECK: %cmp.inv = fcmp olt float %a, %b
+; CHECK-NEXT: %sel = select i1 %cmp.inv, float %a, float %b
+; CHECK-NEXT: ret float %sel
+define float @select_min_uge(float %a, float %b) {
+ %cmp = fcmp uge float %a, %b
+ %sel = select i1 %cmp, float %b, float %a
+ ret float %sel
+}
+
+; CHECK-LABEL: @select_max_ult(
+; CHECK: %cmp.inv = fcmp oge float %a, %b
+; CHECK-NEXT: %sel = select i1 %cmp.inv, float %a, float %b
+; CHECK-NEXT: ret float %sel
+define float @select_max_ult(float %a, float %b) {
+ %cmp = fcmp ult float %a, %b
+ %sel = select i1 %cmp, float %b, float %a
+ ret float %sel
+}
+
+; CHECK-LABEL: @select_max_ule(
+; CHECK: %cmp.inv = fcmp ogt float %a, %b
+; CHECK-NEXT: %sel = select i1 %cmp.inv, float %a, float %b
+; CHECK: ret float %sel
+define float @select_max_ule(float %a, float %b) {
+ %cmp = fcmp ule float %a, %b
+ %sel = select i1 %cmp, float %b, float %a
+ ret float %sel
+}
+
+; CHECK-LABEL: @select_min_ult(
+; CHECK: %cmp.inv = fcmp oge float %a, %b
+; CHECK-NEXT: %sel = select i1 %cmp.inv, float %b, float %a
+; CHECK-NEXT: ret float %sel
+define float @select_min_ult(float %a, float %b) {
+ %cmp = fcmp ult float %a, %b
+ %sel = select i1 %cmp, float %a, float %b
+ ret float %sel
+}
+
+; CHECK-LABEL: @select_min_ule(
+; CHECK: %cmp.inv = fcmp ogt float %a, %b
+; CHECK-NEXT: %sel = select i1 %cmp.inv, float %b, float %a
+; CHECK-NEXT: ret float %sel
+define float @select_min_ule(float %a, float %b) {
+ %cmp = fcmp ule float %a, %b
+ %sel = select i1 %cmp, float %a, float %b
+ ret float %sel
+}
+
+; CHECK-LABEL: @select_fcmp_une(
+; CHECK: %cmp.inv = fcmp oeq float %a, %b
+; CHECK-NEXT: %sel = select i1 %cmp.inv, float %b, float %a
+; CHECK-NEXT: ret float %sel
+define float @select_fcmp_une(float %a, float %b) {
+ %cmp = fcmp une float %a, %b
+ %sel = select i1 %cmp, float %a, float %b
+ ret float %sel
+}
+
+; CHECK-LABEL: @select_fcmp_ueq
+; CHECK: %cmp.inv = fcmp one float %a, %b
+; CHECK-NEXT: %sel = select i1 %cmp.inv, float %b, float %a
+; CHECK-NEXT: ret float %sel
+define float @select_fcmp_ueq(float %a, float %b) {
+ %cmp = fcmp ueq float %a, %b
+ %sel = select i1 %cmp, float %a, float %b
+ ret float %sel
+}
+
+declare void @foo(i1)
+
+; CHECK-LABEL: @select_max_ugt_2_use_cmp(
+; CHECK: fcmp ugt
+; CHECK-NOT: fcmp
+; CHECK: ret
+define float @select_max_ugt_2_use_cmp(float %a, float %b) {
+ %cmp = fcmp ugt float %a, %b
+ call void @foo(i1 %cmp)
+ %sel = select i1 %cmp, float %a, float %b
+ ret float %sel
+}
+
+; CHECK-LABEL: @select_min_uge_2_use_cmp(
+; CHECK: fcmp uge
+; CHECK-NOT: fcmp
+; CHECK: ret
+define float @select_min_uge_2_use_cmp(float %a, float %b) {
+ %cmp = fcmp uge float %a, %b
+ call void @foo(i1 %cmp)
+ %sel = select i1 %cmp, float %b, float %a
+ ret float %sel
+}
Modified: llvm/trunk/test/Transforms/LoopVectorize/minmax_reduction.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopVectorize/minmax_reduction.ll?rev=222705&r1=222704&r2=222705&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/LoopVectorize/minmax_reduction.ll (original)
+++ llvm/trunk/test/Transforms/LoopVectorize/minmax_reduction.ll Mon Nov 24 17:15:18 2014
@@ -516,7 +516,7 @@ for.end:
}
; CHECK-LABEL: @unordered_max_red_float(
-; CHECK: fcmp ugt <2 x float>
+; CHECK: fcmp ole <2 x float>
; CHECK: select <2 x i1>
; CHECK: middle.block
; CHECK: fcmp ogt <2 x float>
@@ -542,7 +542,7 @@ for.end:
}
; CHECK-LABEL: @unordered_max_red_float_ge(
-; CHECK: fcmp uge <2 x float>
+; CHECK: fcmp olt <2 x float>
; CHECK: select <2 x i1>
; CHECK: middle.block
; CHECK: fcmp ogt <2 x float>
@@ -568,7 +568,7 @@ for.end:
}
; CHECK-LABEL: @inverted_unordered_max_red_float(
-; CHECK: fcmp ult <2 x float>
+; CHECK: fcmp oge <2 x float>
; CHECK: select <2 x i1>
; CHECK: middle.block
; CHECK: fcmp ogt <2 x float>
@@ -594,7 +594,7 @@ for.end:
}
; CHECK-LABEL: @inverted_unordered_max_red_float_le(
-; CHECK: fcmp ule <2 x float>
+; CHECK: fcmp ogt <2 x float>
; CHECK: select <2 x i1>
; CHECK: middle.block
; CHECK: fcmp ogt <2 x float>
@@ -727,7 +727,7 @@ for.end:
}
; CHECK-LABEL: @unordered_min_red_float(
-; CHECK: fcmp ult <2 x float>
+; CHECK: fcmp oge <2 x float>
; CHECK: select <2 x i1>
; CHECK: middle.block
; CHECK: fcmp olt <2 x float>
@@ -753,7 +753,7 @@ for.end:
}
; CHECK-LABEL: @unordered_min_red_float_le(
-; CHECK: fcmp ule <2 x float>
+; CHECK: fcmp ogt <2 x float>
; CHECK: select <2 x i1>
; CHECK: middle.block
; CHECK: fcmp olt <2 x float>
@@ -779,7 +779,7 @@ for.end:
}
; CHECK-LABEL: @inverted_unordered_min_red_float(
-; CHECK: fcmp ugt <2 x float>
+; CHECK: fcmp ole <2 x float>
; CHECK: select <2 x i1>
; CHECK: middle.block
; CHECK: fcmp olt <2 x float>
@@ -805,7 +805,7 @@ for.end:
}
; CHECK-LABEL: @inverted_unordered_min_red_float_ge(
-; CHECK: fcmp uge <2 x float>
+; CHECK: fcmp olt <2 x float>
; CHECK: select <2 x i1>
; CHECK: middle.block
; CHECK: fcmp olt <2 x float>
More information about the llvm-commits
mailing list