[llvm] r319538 - [InstSimplify] More fcmp cases when comparing against negative constants.
Florian Hahn via llvm-commits
llvm-commits at lists.llvm.org
Fri Dec 1 04:34:16 PST 2017
Author: fhahn
Date: Fri Dec 1 04:34:16 2017
New Revision: 319538
URL: http://llvm.org/viewvc/llvm-project?rev=319538&view=rev
Log:
[InstSimplify] More fcmp cases when comparing against negative constants.
Summary:
For known positive non-zero value X:
fcmp uge X, -C => true
fcmp ugt X, -C => true
fcmp une X, -C => true
fcmp oeq X, -C => false
fcmp ole X, -C => false
fcmp olt X, -C => false
Patch by Paul Walker.
Reviewers: majnemer, t.p.northover, spatel, RKSimon
Reviewed By: spatel
Subscribers: fhahn, llvm-commits
Differential Revision: https://reviews.llvm.org/D40012
Modified:
llvm/trunk/lib/Analysis/InstructionSimplify.cpp
llvm/trunk/test/Transforms/InstCombine/cast-int-fcmp-eq-0.ll
llvm/trunk/test/Transforms/InstSimplify/floating-point-compare.ll
Modified: llvm/trunk/lib/Analysis/InstructionSimplify.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/InstructionSimplify.cpp?rev=319538&r1=319537&r2=319538&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/InstructionSimplify.cpp (original)
+++ llvm/trunk/lib/Analysis/InstructionSimplify.cpp Fri Dec 1 04:34:16 2017
@@ -3378,6 +3378,28 @@ static Value *SimplifyFCmpInst(unsigned
default:
break;
}
+ } else if (C->isNegative()) {
+ assert(!C->isNaN() && "Unexpected NaN constant!");
+ // TODO: We can catch more cases by using a range check rather than
+ // relying on CannotBeOrderedLessThanZero.
+ switch (Pred) {
+ case FCmpInst::FCMP_UGE:
+ case FCmpInst::FCMP_UGT:
+ case FCmpInst::FCMP_UNE:
+ // (X >= 0) implies (X > C) when (C < 0)
+ if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
+ return getTrue(RetTy);
+ break;
+ case FCmpInst::FCMP_OEQ:
+ case FCmpInst::FCMP_OLE:
+ case FCmpInst::FCMP_OLT:
+ // (X >= 0) implies !(X < C) when (C < 0)
+ if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
+ return getFalse(RetTy);
+ break;
+ default:
+ break;
+ }
}
}
Modified: llvm/trunk/test/Transforms/InstCombine/cast-int-fcmp-eq-0.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/cast-int-fcmp-eq-0.ll?rev=319538&r1=319537&r2=319538&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/cast-int-fcmp-eq-0.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/cast-int-fcmp-eq-0.ll Fri Dec 1 04:34:16 2017
@@ -198,14 +198,6 @@ define i1 @i32_cast_cmp_ole_int_0_sitofp
ret i1 %cmp
}
-; CHECK-LABEL: @i32_cast_cmp_olt_int_0_uitofp(
-; CHECK: ret i1 false
-define i1 @i32_cast_cmp_olt_int_0_uitofp(i32 %i) {
- %f = uitofp i32 %i to float
- %cmp = fcmp olt float %f, 0.0
- ret i1 %cmp
-}
-
; CHECK-LABEL: @i32_cast_cmp_olt_int_0_sitofp(
; CHECK: icmp slt i32 %i, 0
; CHECK-NEXT: ret
@@ -339,16 +331,6 @@ define i1 @i32_cast_cmp_oeq_int_i32umax_
ret i1 %cmp
}
-; CHECK-LABEL: @i32_cast_cmp_oeq_int_i32imin_uitofp(
-; CHECK: uitofp
-; CHECK: fcmp oeq
-; CHECK-NEXT: ret
-define i1 @i32_cast_cmp_oeq_int_i32imin_uitofp(i32 %i) {
- %f = uitofp i32 %i to float
- %cmp = fcmp oeq float %f, 0xC1E0000000000000
- ret i1 %cmp
-}
-
; CHECK-LABEL: @i32_cast_cmp_oeq_int_i32imin_sitofp(
; CHECK: sitofp
; CHECK: fcmp oeq
@@ -379,16 +361,6 @@ define i1 @i32_cast_cmp_oeq_int_i32imax_
ret i1 %cmp
}
-; CHECK-LABEL: @i32_cast_cmp_oeq_int_negi32umax_uitofp(
-; CHECK: uitofp
-; CHECK: fcmp oeq
-; CHECK-NEXT: ret
-define i1 @i32_cast_cmp_oeq_int_negi32umax_uitofp(i32 %i) {
- %f = uitofp i32 %i to float
- %cmp = fcmp oeq float %f, 0xC1F0000000000000
- ret i1 %cmp
-}
-
; 32-bit signed integer cannot possibly round to -1<<32
; CHECK-LABEL: @i32_cast_cmp_oeq_int_negi32umax_sitofp(
; CHECK-NEXT: ret i1 false
Modified: llvm/trunk/test/Transforms/InstSimplify/floating-point-compare.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstSimplify/floating-point-compare.ll?rev=319538&r1=319537&r2=319538&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstSimplify/floating-point-compare.ll (original)
+++ llvm/trunk/test/Transforms/InstSimplify/floating-point-compare.ll Fri Dec 1 04:34:16 2017
@@ -169,8 +169,10 @@ define i1 @one_with_self(double %arg) {
; and between uge and olt, to give reasonble coverage
; without combinatorial explosion.
+declare half @llvm.fabs.f16(half)
declare float @llvm.fabs.f32(float)
declare double @llvm.fabs.f64(double)
+declare <2 x float> @llvm.fabs.v2f32(<2 x float>)
declare <2 x double> @llvm.fabs.v2f64(<2 x double>)
declare float @llvm.sqrt.f32(float)
declare double @llvm.powi.f64(double,i32)
@@ -276,45 +278,55 @@ define i1 @orderedLessZeroMaxNum(float,
define i1 @known_positive_olt_with_negative_constant(double %a) {
; CHECK-LABEL: @known_positive_olt_with_negative_constant(
-; CHECK-NEXT: [[CALL:%.*]] = call double @llvm.fabs.f64(double %a)
-; CHECK-NEXT: [[CMP:%.*]] = fcmp olt double [[CALL]], -1.000000e+00
-; CHECK-NEXT: ret i1 [[CMP]]
+; CHECK-NEXT: ret i1 false
;
%call = call double @llvm.fabs.f64(double %a)
%cmp = fcmp olt double %call, -1.0
ret i1 %cmp
}
-define <2 x i1> @known_positive_ole_with_negative_constant_splat_vec(<2 x double> %a) {
+define <2 x i1> @known_positive_ole_with_negative_constant_splat_vec(<2 x i32> %a) {
; CHECK-LABEL: @known_positive_ole_with_negative_constant_splat_vec(
-; CHECK-NEXT: [[CALL:%.*]] = call <2 x double> @llvm.fabs.v2f64(<2 x double> %a)
-; CHECK-NEXT: [[CMP:%.*]] = fcmp ole <2 x double> [[CALL]], <double -2.000000e+00, double -2.000000e+00>
-; CHECK-NEXT: ret <2 x i1> [[CMP]]
+; CHECK-NEXT: ret <2 x i1> zeroinitializer
;
- %call = call <2 x double> @llvm.fabs.v2f64(<2 x double> %a)
+ %call = uitofp <2 x i32> %a to <2 x double>
%cmp = fcmp ole <2 x double> %call, <double -2.0, double -2.0>
ret <2 x i1> %cmp
}
-define i1 @known_positive_ugt_with_negative_constant(double %a) {
+define i1 @known_positive_ugt_with_negative_constant(i32 %a) {
; CHECK-LABEL: @known_positive_ugt_with_negative_constant(
-; CHECK-NEXT: [[CALL:%.*]] = call double @llvm.fabs.f64(double %a)
-; CHECK-NEXT: [[CMP:%.*]] = fcmp ugt double [[CALL]], -3.000000e+00
-; CHECK-NEXT: ret i1 [[CMP]]
+; CHECK-NEXT: ret i1 true
;
- %call = call double @llvm.fabs.f64(double %a)
- %cmp = fcmp ugt double %call, -3.0
+ %call = uitofp i32 %a to float
+ %cmp = fcmp ugt float %call, -3.0
ret i1 %cmp
}
-define <2 x i1> @known_positive_uge_with_negative_constant_splat_vec(<2 x double> %a) {
+define <2 x i1> @known_positive_uge_with_negative_constant_splat_vec(<2 x float> %a) {
; CHECK-LABEL: @known_positive_uge_with_negative_constant_splat_vec(
-; CHECK-NEXT: [[CALL:%.*]] = call <2 x double> @llvm.fabs.v2f64(<2 x double> %a)
-; CHECK-NEXT: [[CMP:%.*]] = fcmp uge <2 x double> [[CALL]], <double -4.000000e+00, double -4.000000e+00>
-; CHECK-NEXT: ret <2 x i1> [[CMP]]
+; CHECK-NEXT: ret <2 x i1> <i1 true, i1 true>
+;
+ %call = call <2 x float> @llvm.fabs.v2f32(<2 x float> %a)
+ %cmp = fcmp uge <2 x float> %call, <float -4.0, float -4.0>
+ ret <2 x i1> %cmp
+}
+
+define i1 @known_positive_oeq_with_negative_constant(half %a) {
+; CHECK-LABEL: @known_positive_oeq_with_negative_constant(
+; CHECK-NEXT: ret i1 false
+;
+ %call = call half @llvm.fabs.f16(half %a)
+ %cmp = fcmp oeq half %call, -5.0
+ ret i1 %cmp
+}
+
+define <2 x i1> @known_positive_une_with_negative_constant_splat_vec(<2 x i32> %a) {
+; CHECK-LABEL: @known_positive_une_with_negative_constant_splat_vec(
+; CHECK-NEXT: ret <2 x i1> <i1 true, i1 true>
;
- %call = call <2 x double> @llvm.fabs.v2f64(<2 x double> %a)
- %cmp = fcmp uge <2 x double> %call, <double -4.0, double -4.0>
+ %call = uitofp <2 x i32> %a to <2 x half>
+ %cmp = fcmp une <2 x half> %call, <half -6.0, half -6.0>
ret <2 x i1> %cmp
}
More information about the llvm-commits
mailing list