[llvm] r316795 - Improve clamp recognition in ValueTracking.
Artur Gainullin via llvm-commits
llvm-commits at lists.llvm.org
Fri Oct 27 13:53:41 PDT 2017
Author: arturgainullin
Date: Fri Oct 27 13:53:41 2017
New Revision: 316795
URL: http://llvm.org/viewvc/llvm-project?rev=316795&view=rev
Log:
Improve clamp recognition in ValueTracking.
Summary:
ValueTracking was recognizing not all variations of clamp. Swapping of
true value and false value of select was added to fix this problem. The
first patch was reverted because it caused miscompile in NVPTX target.
Added corresponding test cases.
Reviewers: spatel, majnemer, efriedma, reames
Subscribers: llvm-commits, jholewinski
Differential Revision: https://reviews.llvm.org/D39240
Added:
llvm/trunk/test/CodeGen/NVPTX/minmax-negative.ll
Modified:
llvm/trunk/lib/Analysis/ValueTracking.cpp
llvm/trunk/test/Transforms/InstCombine/minmax-fold.ll
Modified: llvm/trunk/lib/Analysis/ValueTracking.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ValueTracking.cpp?rev=316795&r1=316794&r2=316795&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ValueTracking.cpp (original)
+++ llvm/trunk/lib/Analysis/ValueTracking.cpp Fri Oct 27 13:53:41 2017
@@ -4063,21 +4063,19 @@ static SelectPatternResult matchFastFloa
return {SPF_UNKNOWN, SPNB_NA, false};
}
-/// Match non-obvious integer minimum and maximum sequences.
-static SelectPatternResult matchMinMax(CmpInst::Predicate Pred,
- Value *CmpLHS, Value *CmpRHS,
- Value *TrueVal, Value *FalseVal,
- Value *&LHS, Value *&RHS) {
- // Assume success. If there's no match, callers should not use these anyway.
- LHS = TrueVal;
- RHS = FalseVal;
-
- // Recognize variations of:
- // CLAMP(v,l,h) ==> ((v) < (l) ? (l) : ((v) > (h) ? (h) : (v)))
+/// Recognize variations of:
+/// CLAMP(v,l,h) ==> ((v) < (l) ? (l) : ((v) > (h) ? (h) : (v)))
+static SelectPatternResult matchClamp(CmpInst::Predicate Pred,
+ Value *CmpLHS, Value *CmpRHS,
+ Value *TrueVal, Value *FalseVal) {
+ // Swap the select operands and predicate to match the patterns below.
+ if (CmpRHS != TrueVal) {
+ Pred = ICmpInst::getSwappedPredicate(Pred);
+ std::swap(TrueVal, FalseVal);
+ }
const APInt *C1;
if (CmpRHS == TrueVal && match(CmpRHS, m_APInt(C1))) {
const APInt *C2;
-
// (X <s C1) ? C1 : SMIN(X, C2) ==> SMAX(SMIN(X, C2), C1)
if (match(FalseVal, m_SMin(m_Specific(CmpLHS), m_APInt(C2))) &&
C1->slt(*C2) && Pred == CmpInst::ICMP_SLT)
@@ -4098,6 +4096,21 @@ static SelectPatternResult matchMinMax(C
C1->ugt(*C2) && Pred == CmpInst::ICMP_UGT)
return {SPF_UMIN, SPNB_NA, false};
}
+ return {SPF_UNKNOWN, SPNB_NA, false};
+}
+
+/// Match non-obvious integer minimum and maximum sequences.
+static SelectPatternResult matchMinMax(CmpInst::Predicate Pred,
+ Value *CmpLHS, Value *CmpRHS,
+ Value *TrueVal, Value *FalseVal,
+ Value *&LHS, Value *&RHS) {
+ // Assume success. If there's no match, callers should not use these anyway.
+ LHS = TrueVal;
+ RHS = FalseVal;
+
+ SelectPatternResult SPR = matchClamp(Pred, CmpLHS, CmpRHS, TrueVal, FalseVal);
+ if (SPR.Flavor != SelectPatternFlavor::SPF_UNKNOWN)
+ return SPR;
if (Pred != CmpInst::ICMP_SGT && Pred != CmpInst::ICMP_SLT)
return {SPF_UNKNOWN, SPNB_NA, false};
@@ -4116,6 +4129,7 @@ static SelectPatternResult matchMinMax(C
match(TrueVal, m_NSWSub(m_Specific(CmpLHS), m_Specific(CmpRHS))))
return {Pred == CmpInst::ICMP_SGT ? SPF_SMAX : SPF_SMIN, SPNB_NA, false};
+ const APInt *C1;
if (!match(CmpRHS, m_APInt(C1)))
return {SPF_UNKNOWN, SPNB_NA, false};
Added: llvm/trunk/test/CodeGen/NVPTX/minmax-negative.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/NVPTX/minmax-negative.ll?rev=316795&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/NVPTX/minmax-negative.ll (added)
+++ llvm/trunk/test/CodeGen/NVPTX/minmax-negative.ll Fri Oct 27 13:53:41 2017
@@ -0,0 +1,9 @@
+; RUN: llc < %s -march=nvptx -O0 | FileCheck %s
+
+define i16 @test1(i16* %sur1) {
+; CHECK-NOT: mov.u16 %rs{{[0-9]+}}, 32767
+ %_tmp21.i = icmp sle i16 0, 0
+ %_tmp22.i = select i1 %_tmp21.i, i16 0, i16 32767
+ store i16 %_tmp22.i, i16* %sur1
+ ret i16 0
+}
Modified: llvm/trunk/test/Transforms/InstCombine/minmax-fold.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/minmax-fold.ll?rev=316795&r1=316794&r2=316795&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/minmax-fold.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/minmax-fold.ll Fri Oct 27 13:53:41 2017
@@ -404,8 +404,8 @@ define i32 @clamp_signed3(i32 %x) {
; CHECK-LABEL: @clamp_signed3(
; CHECK-NEXT: [[CMP2:%.*]] = icmp slt i32 [[X:%.*]], 255
; CHECK-NEXT: [[MIN:%.*]] = select i1 [[CMP2]], i32 [[X]], i32 255
-; CHECK-NEXT: [[CMP1:%.*]] = icmp sgt i32 [[X]], 15
-; CHECK-NEXT: [[R:%.*]] = select i1 [[CMP1]], i32 [[MIN]], i32 15
+; CHECK-NEXT: [[TMP1:%.*]] = icmp sgt i32 [[MIN]], 15
+; CHECK-NEXT: [[R:%.*]] = select i1 [[TMP1]], i32 [[MIN]], i32 15
; CHECK-NEXT: ret i32 [[R]]
;
%cmp2 = icmp slt i32 %x, 255
@@ -421,8 +421,8 @@ define i32 @clamp_signed4(i32 %x) {
; CHECK-LABEL: @clamp_signed4(
; CHECK-NEXT: [[CMP2:%.*]] = icmp sgt i32 [[X:%.*]], 15
; CHECK-NEXT: [[MAX:%.*]] = select i1 [[CMP2]], i32 [[X]], i32 15
-; CHECK-NEXT: [[CMP1:%.*]] = icmp slt i32 [[X]], 255
-; CHECK-NEXT: [[R:%.*]] = select i1 [[CMP1]], i32 [[MAX]], i32 255
+; CHECK-NEXT: [[TMP1:%.*]] = icmp slt i32 [[MAX]], 255
+; CHECK-NEXT: [[R:%.*]] = select i1 [[TMP1]], i32 [[MAX]], i32 255
; CHECK-NEXT: ret i32 [[R]]
;
%cmp2 = icmp sgt i32 %x, 15
@@ -472,8 +472,8 @@ define i32 @clamp_unsigned3(i32 %x) {
; CHECK-LABEL: @clamp_unsigned3(
; CHECK-NEXT: [[CMP2:%.*]] = icmp ult i32 [[X:%.*]], 255
; CHECK-NEXT: [[MIN:%.*]] = select i1 [[CMP2]], i32 [[X]], i32 255
-; CHECK-NEXT: [[CMP1:%.*]] = icmp ugt i32 [[X]], 15
-; CHECK-NEXT: [[R:%.*]] = select i1 [[CMP1]], i32 [[MIN]], i32 15
+; CHECK-NEXT: [[TMP1:%.*]] = icmp ugt i32 [[MIN]], 15
+; CHECK-NEXT: [[R:%.*]] = select i1 [[TMP1]], i32 [[MIN]], i32 15
; CHECK-NEXT: ret i32 [[R]]
;
%cmp2 = icmp ult i32 %x, 255
@@ -489,8 +489,8 @@ define i32 @clamp_unsigned4(i32 %x) {
; CHECK-LABEL: @clamp_unsigned4(
; CHECK-NEXT: [[CMP2:%.*]] = icmp ugt i32 [[X:%.*]], 15
; CHECK-NEXT: [[MAX:%.*]] = select i1 [[CMP2]], i32 [[X]], i32 15
-; CHECK-NEXT: [[CMP1:%.*]] = icmp ult i32 [[X]], 255
-; CHECK-NEXT: [[R:%.*]] = select i1 [[CMP1]], i32 [[MAX]], i32 255
+; CHECK-NEXT: [[TMP1:%.*]] = icmp ult i32 [[MAX]], 255
+; CHECK-NEXT: [[R:%.*]] = select i1 [[TMP1]], i32 [[MAX]], i32 255
; CHECK-NEXT: ret i32 [[R]]
;
%cmp2 = icmp ugt i32 %x, 15
@@ -523,8 +523,8 @@ define i32 @clamp_check_for_no_infinite_
; CHECK-LABEL: @clamp_check_for_no_infinite_loop2(
; CHECK-NEXT: [[CMP1:%.*]] = icmp sgt i32 [[I:%.*]], -255
; CHECK-NEXT: [[SEL1:%.*]] = select i1 [[CMP1]], i32 [[I]], i32 -255
-; CHECK-NEXT: [[CMP2:%.*]] = icmp slt i32 [[I]], 0
-; CHECK-NEXT: [[RES:%.*]] = select i1 [[CMP2]], i32 [[SEL1]], i32 0
+; CHECK-NEXT: [[TMP1:%.*]] = icmp slt i32 [[SEL1]], 0
+; CHECK-NEXT: [[RES:%.*]] = select i1 [[TMP1]], i32 [[SEL1]], i32 0
; CHECK-NEXT: ret i32 [[RES]]
;
%cmp1 = icmp sgt i32 %i, -255
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