[llvm] 1901f44 - [InstCombine] Handle more even/odd math functions (#81324)
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Sat Feb 24 05:35:40 PST 2024
Author: Artem Tyurin
Date: 2024-02-24T21:35:35+08:00
New Revision: 1901f442ca6374787e6810adb573d138f80893dd
URL: https://github.com/llvm/llvm-project/commit/1901f442ca6374787e6810adb573d138f80893dd
DIFF: https://github.com/llvm/llvm-project/commit/1901f442ca6374787e6810adb573d138f80893dd.diff
LOG: [InstCombine] Handle more even/odd math functions (#81324)
At the moment this PR adds support only for `erf` function.
Fixes #77220.
Added:
llvm/test/Transforms/InstCombine/math-odd-even-parity.ll
Modified:
llvm/include/llvm/Analysis/TargetLibraryInfo.def
llvm/include/llvm/Transforms/Utils/SimplifyLibCalls.h
llvm/lib/Analysis/TargetLibraryInfo.cpp
llvm/lib/Transforms/Utils/BuildLibCalls.cpp
llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
llvm/test/tools/llvm-tli-checker/ps4-tli-check.yaml
llvm/unittests/Analysis/TargetLibraryInfoTest.cpp
Removed:
################################################################################
diff --git a/llvm/include/llvm/Analysis/TargetLibraryInfo.def b/llvm/include/llvm/Analysis/TargetLibraryInfo.def
index 6bd922eed89e15..37221eb9e47115 100644
--- a/llvm/include/llvm/Analysis/TargetLibraryInfo.def
+++ b/llvm/include/llvm/Analysis/TargetLibraryInfo.def
@@ -1069,6 +1069,21 @@ TLI_DEFINE_ENUM_INTERNAL(ctermid)
TLI_DEFINE_STRING_INTERNAL("ctermid")
TLI_DEFINE_SIG_INTERNAL(Ptr, Ptr)
+/// double erf(double x);
+TLI_DEFINE_ENUM_INTERNAL(erf)
+TLI_DEFINE_STRING_INTERNAL("erf")
+TLI_DEFINE_SIG_INTERNAL(Dbl, Dbl)
+
+/// float erff(float x);
+TLI_DEFINE_ENUM_INTERNAL(erff)
+TLI_DEFINE_STRING_INTERNAL("erff")
+TLI_DEFINE_SIG_INTERNAL(Flt, Flt)
+
+/// long double erfl(long double x);
+TLI_DEFINE_ENUM_INTERNAL(erfl)
+TLI_DEFINE_STRING_INTERNAL("erfl")
+TLI_DEFINE_SIG_INTERNAL(LDbl, LDbl)
+
/// int execl(const char *path, const char *arg, ...);
TLI_DEFINE_ENUM_INTERNAL(execl)
TLI_DEFINE_STRING_INTERNAL("execl")
diff --git a/llvm/include/llvm/Transforms/Utils/SimplifyLibCalls.h b/llvm/include/llvm/Transforms/Utils/SimplifyLibCalls.h
index 1b6b525b19caef..e2682b429e9dbf 100644
--- a/llvm/include/llvm/Transforms/Utils/SimplifyLibCalls.h
+++ b/llvm/include/llvm/Transforms/Utils/SimplifyLibCalls.h
@@ -204,6 +204,7 @@ class LibCallSimplifier {
Value *mergeSqrtToExp(CallInst *CI, IRBuilderBase &B);
Value *optimizeSinCosPi(CallInst *CI, bool IsSin, IRBuilderBase &B);
Value *optimizeTrigInversionPairs(CallInst *CI, IRBuilderBase &B);
+ Value *optimizeSymmetric(CallInst *CI, LibFunc Func, IRBuilderBase &B);
// Wrapper for all floating point library call optimizations
Value *optimizeFloatingPointLibCall(CallInst *CI, LibFunc Func,
IRBuilderBase &B);
diff --git a/llvm/lib/Analysis/TargetLibraryInfo.cpp b/llvm/lib/Analysis/TargetLibraryInfo.cpp
index 710762a6c0ad1d..835268bb2d8528 100644
--- a/llvm/lib/Analysis/TargetLibraryInfo.cpp
+++ b/llvm/lib/Analysis/TargetLibraryInfo.cpp
@@ -808,6 +808,9 @@ static void initialize(TargetLibraryInfoImpl &TLI, const Triple &T,
TLI.setUnavailable(LibFunc_cabs);
TLI.setUnavailable(LibFunc_cabsf);
TLI.setUnavailable(LibFunc_cabsl);
+ TLI.setUnavailable(LibFunc_erf);
+ TLI.setUnavailable(LibFunc_erff);
+ TLI.setUnavailable(LibFunc_erfl);
TLI.setUnavailable(LibFunc_ffs);
TLI.setUnavailable(LibFunc_flockfile);
TLI.setUnavailable(LibFunc_fseeko);
diff --git a/llvm/lib/Transforms/Utils/BuildLibCalls.cpp b/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
index 12741dc5af5a1d..ed0ed345435c45 100644
--- a/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
@@ -1137,6 +1137,9 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
case LibFunc_cosl:
case LibFunc_cospi:
case LibFunc_cospif:
+ case LibFunc_erf:
+ case LibFunc_erff:
+ case LibFunc_erfl:
case LibFunc_exp:
case LibFunc_expf:
case LibFunc_expl:
diff --git a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
index 26a34aa99e1b87..2e68a9c01898c8 100644
--- a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -1908,49 +1908,6 @@ Value *LibCallSimplifier::optimizeCAbs(CallInst *CI, IRBuilderBase &B) {
*CI, B.CreateCall(FSqrt, B.CreateFAdd(RealReal, ImagImag), "cabs"));
}
-static Value *optimizeTrigReflections(CallInst *Call, LibFunc Func,
- IRBuilderBase &B) {
- if (!isa<FPMathOperator>(Call))
- return nullptr;
-
- IRBuilderBase::FastMathFlagGuard Guard(B);
- B.setFastMathFlags(Call->getFastMathFlags());
-
- // TODO: Can this be shared to also handle LLVM intrinsics?
- Value *X;
- switch (Func) {
- case LibFunc_sin:
- case LibFunc_sinf:
- case LibFunc_sinl:
- case LibFunc_tan:
- case LibFunc_tanf:
- case LibFunc_tanl:
- // sin(-X) --> -sin(X)
- // tan(-X) --> -tan(X)
- if (match(Call->getArgOperand(0), m_OneUse(m_FNeg(m_Value(X)))))
- return B.CreateFNeg(
- copyFlags(*Call, B.CreateCall(Call->getCalledFunction(), X)));
- break;
- case LibFunc_cos:
- case LibFunc_cosf:
- case LibFunc_cosl: {
- // cos(-x) --> cos(x)
- // cos(fabs(x)) --> cos(x)
- // cos(copysign(x, y)) --> cos(x)
- Value *Sign;
- Value *Src = Call->getArgOperand(0);
- if (match(Src, m_FNeg(m_Value(X))) || match(Src, m_FAbs(m_Value(X))) ||
- match(Src, m_CopySign(m_Value(X), m_Value(Sign))))
- return copyFlags(*Call,
- B.CreateCall(Call->getCalledFunction(), X, "cos"));
- break;
- }
- default:
- break;
- }
- return nullptr;
-}
-
// Return a properly extended integer (DstWidth bits wide) if the operation is
// an itofp.
static Value *getIntToFPVal(Value *I2F, IRBuilderBase &B, unsigned DstWidth) {
@@ -2797,6 +2754,63 @@ static bool insertSinCosCall(IRBuilderBase &B, Function *OrigCallee, Value *Arg,
return true;
}
+static Value *optimizeSymmetricCall(CallInst *CI, bool IsEven,
+ IRBuilderBase &B) {
+ Value *X;
+ Value *Src = CI->getArgOperand(0);
+
+ if (match(Src, m_OneUse(m_FNeg(m_Value(X))))) {
+ IRBuilderBase::FastMathFlagGuard Guard(B);
+ B.setFastMathFlags(CI->getFastMathFlags());
+
+ auto *CallInst = copyFlags(*CI, B.CreateCall(CI->getCalledFunction(), {X}));
+ if (IsEven) {
+ // Even function: f(-x) = f(x)
+ return CallInst;
+ }
+ // Odd function: f(-x) = -f(x)
+ return B.CreateFNeg(CallInst);
+ }
+
+ // Even function: f(abs(x)) = f(x), f(copysign(x, y)) = f(x)
+ if (IsEven && (match(Src, m_FAbs(m_Value(X))) ||
+ match(Src, m_CopySign(m_Value(X), m_Value())))) {
+ IRBuilderBase::FastMathFlagGuard Guard(B);
+ B.setFastMathFlags(CI->getFastMathFlags());
+
+ auto *CallInst = copyFlags(*CI, B.CreateCall(CI->getCalledFunction(), {X}));
+ return CallInst;
+ }
+
+ return nullptr;
+}
+
+Value *LibCallSimplifier::optimizeSymmetric(CallInst *CI, LibFunc Func,
+ IRBuilderBase &B) {
+ switch (Func) {
+ case LibFunc_cos:
+ case LibFunc_cosf:
+ case LibFunc_cosl:
+ return optimizeSymmetricCall(CI, /*IsEven*/ true, B);
+
+ case LibFunc_sin:
+ case LibFunc_sinf:
+ case LibFunc_sinl:
+
+ case LibFunc_tan:
+ case LibFunc_tanf:
+ case LibFunc_tanl:
+
+ case LibFunc_erf:
+ case LibFunc_erff:
+ case LibFunc_erfl:
+ return optimizeSymmetricCall(CI, /*IsEven*/ false, B);
+
+ default:
+ return nullptr;
+ }
+}
+
Value *LibCallSimplifier::optimizeSinCosPi(CallInst *CI, bool IsSin, IRBuilderBase &B) {
// Make sure the prototype is as expected, otherwise the rest of the
// function is probably invalid and likely to abort.
@@ -3678,7 +3692,7 @@ Value *LibCallSimplifier::optimizeFloatingPointLibCall(CallInst *CI,
if (CI->isStrictFP())
return nullptr;
- if (Value *V = optimizeTrigReflections(CI, Func, Builder))
+ if (Value *V = optimizeSymmetric(CI, Func, Builder))
return V;
switch (Func) {
diff --git a/llvm/test/Transforms/InstCombine/math-odd-even-parity.ll b/llvm/test/Transforms/InstCombine/math-odd-even-parity.ll
new file mode 100644
index 00000000000000..4c8cf7a99d895f
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/math-odd-even-parity.ll
@@ -0,0 +1,50 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
+; RUN: opt < %s -passes=instcombine -S | FileCheck %s
+
+declare double @erf(double)
+declare double @cos(double)
+declare double @fabs(double)
+
+declare void @use(double) nounwind
+
+; Check odd parity: -erf(-x) == erf(x)
+define double @test_erf(double %x) {
+; CHECK-LABEL: define double @test_erf(
+; CHECK-SAME: double [[X:%.*]]) {
+; CHECK-NEXT: [[RES:%.*]] = tail call reassoc double @erf(double [[X]])
+; CHECK-NEXT: ret double [[RES]]
+;
+ %neg_x = fneg double %x
+ %res = tail call reassoc double @erf(double %neg_x)
+ %neg_res = fneg double %res
+ ret double %neg_res
+}
+
+; Check even parity: cos(fabs(x)) == cos(x)
+define double @test_cos_fabs(double %x) {
+; CHECK-LABEL: define double @test_cos_fabs(
+; CHECK-SAME: double [[X:%.*]]) {
+; CHECK-NEXT: [[RES:%.*]] = tail call reassoc double @cos(double [[X]])
+; CHECK-NEXT: ret double [[RES]]
+;
+ %fabs_res = call double @fabs(double %x)
+ %res = tail call reassoc double @cos(double %fabs_res)
+ ret double %res
+}
+
+; Do nothing in case of multi-use
+define double @test_erf_multi_use(double %x) {
+; CHECK-LABEL: define double @test_erf_multi_use(
+; CHECK-SAME: double [[X:%.*]]) {
+; CHECK-NEXT: [[NEG_X:%.*]] = fneg double [[X]]
+; CHECK-NEXT: call void @use(double [[NEG_X]])
+; CHECK-NEXT: [[RES:%.*]] = call double @erf(double [[NEG_X]])
+; CHECK-NEXT: [[NEG_RES:%.*]] = fneg double [[RES]]
+; CHECK-NEXT: ret double [[NEG_RES]]
+;
+ %neg_x = fneg double %x
+ call void @use(double %neg_x)
+ %res = call double @erf(double %neg_x)
+ %neg_res = fneg double %res
+ ret double %neg_res
+}
diff --git a/llvm/test/tools/llvm-tli-checker/ps4-tli-check.yaml b/llvm/test/tools/llvm-tli-checker/ps4-tli-check.yaml
index 23d3482fb89a78..61caf727b0f96e 100644
--- a/llvm/test/tools/llvm-tli-checker/ps4-tli-check.yaml
+++ b/llvm/test/tools/llvm-tli-checker/ps4-tli-check.yaml
@@ -47,10 +47,10 @@
## the exact count first; the two directives should add up to that.
## Yes, this means additions to TLI will fail this test, but the argument
## to -COUNT can't be an expression.
-# AVAIL: TLI knows 476 symbols, 243 available
+# AVAIL: TLI knows 479 symbols, 243 available
# AVAIL-COUNT-243: {{^}} available
# AVAIL-NOT: {{^}} available
-# UNAVAIL-COUNT-233: not available
+# UNAVAIL-COUNT-236: not available
# UNAVAIL-NOT: not available
## This is a large file so it's worth telling lit to stop here.
diff --git a/llvm/unittests/Analysis/TargetLibraryInfoTest.cpp b/llvm/unittests/Analysis/TargetLibraryInfoTest.cpp
index 34b06fe480f364..8e3fe3b44a84a9 100644
--- a/llvm/unittests/Analysis/TargetLibraryInfoTest.cpp
+++ b/llvm/unittests/Analysis/TargetLibraryInfoTest.cpp
@@ -264,6 +264,9 @@ TEST_F(TargetLibraryInfoTest, ValidProto) {
"declare double @pow(double, double)\n"
"declare float @powf(float, float)\n"
"declare x86_fp80 @powl(x86_fp80, x86_fp80)\n"
+ "declare double @erf(double)\n"
+ "declare float @erff(float)\n"
+ "declare x86_fp80 @erfl(x86_fp80)\n"
"declare i32 @printf(i8*, ...)\n"
"declare i32 @putc(i32, %struct*)\n"
"declare i32 @putc_unlocked(i32, %struct*)\n"
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