<div dir="ltr"><div>Sure, I can do that. Make sure I'm not missing any corner cases: we already do the right thing for the regular FP opcodes via checks for BinaryOperator / UnaryOperator, but we miss all FP intrinsics currently?</div><div><br></div><div>Started adding tests here:</div><div><a href="https://github.com/llvm/llvm-project/commit/572e506b55f0ad181ddbb04d889651caa5a287e8">https://github.com/llvm/llvm-project/commit/572e506b55f0ad181ddbb04d889651caa5a287e8</a></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Jun 16, 2021 at 11:40 AM Philip Reames <<a href="mailto:listmail@philipreames.com" target="_blank">listmail@philipreames.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">This is long overdue. Thanks. :)<br>
<br>
Can I ask you to also update propagatesPoison in ValueTracking?<br>
<br>
Philip<br>
<br>
On 6/16/21 8:33 AM, Sanjay Patel via llvm-commits wrote:<br>
> Author: Sanjay Patel<br>
> Date: 2021-06-16T11:31:58-04:00<br>
> New Revision: ce95200b7942bb0683fd491800bbd9e1dc908e04<br>
><br>
> URL: <a href="https://github.com/llvm/llvm-project/commit/ce95200b7942bb0683fd491800bbd9e1dc908e04" rel="noreferrer" target="_blank">https://github.com/llvm/llvm-project/commit/ce95200b7942bb0683fd491800bbd9e1dc908e04</a><br>
> DIFF: <a href="https://github.com/llvm/llvm-project/commit/ce95200b7942bb0683fd491800bbd9e1dc908e04.diff" rel="noreferrer" target="_blank">https://github.com/llvm/llvm-project/commit/ce95200b7942bb0683fd491800bbd9e1dc908e04.diff</a><br>
><br>
> LOG: [InstSimplify] propagate poison through FP ops<br>
><br>
> We already have this fold:<br>
> fadd float poison, 1.0 --> poison<br>
> ...via ConstantFolding, so this makes the behavior consistent<br>
> if the other operand(s) are non-constant.<br>
><br>
> The fold for undef was added before poison existed as a<br>
> value/type in IR.<br>
><br>
> This came up in D102673 / D103169<br>
> because we're trying to sort out the more complicated handling<br>
> for constrained math ops.<br>
> We should have the handling for the regular instructions done<br>
> first, so we can build on that (or diverge as needed).<br>
><br>
> Differential Revision: <a href="https://reviews.llvm.org/D104383" rel="noreferrer" target="_blank">https://reviews.llvm.org/D104383</a><br>
><br>
> Added:<br>
> <br>
><br>
> Modified:<br>
> llvm/lib/Analysis/InstructionSimplify.cpp<br>
> llvm/test/Transforms/InstSimplify/call.ll<br>
> llvm/test/Transforms/InstSimplify/fp-undef-poison.ll<br>
><br>
> Removed:<br>
> <br>
><br>
><br>
> ################################################################################<br>
> diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp<br>
> index 7fb7a394e86ab..895218bea9f33 100644<br>
> --- a/llvm/lib/Analysis/InstructionSimplify.cpp<br>
> +++ b/llvm/lib/Analysis/InstructionSimplify.cpp<br>
> @@ -4807,12 +4807,16 @@ static Constant *propagateNaN(Constant *In) {<br>
> }<br>
> <br>
> /// Perform folds that are common to any floating-point operation. This implies<br>
> -/// transforms based on undef/NaN because the operation itself makes no<br>
> +/// transforms based on poison/undef/NaN because the operation itself makes no<br>
> ///<br>
> diff erence to the result.<br>
> -static Constant *simplifyFPOp(ArrayRef<Value *> Ops,<br>
> - FastMathFlags FMF,<br>
> +static Constant *simplifyFPOp(ArrayRef<Value *> Ops, FastMathFlags FMF,<br>
> const SimplifyQuery &Q) {<br>
> for (Value *V : Ops) {<br>
> + // Poison is independent of anything else. It always propagates from an<br>
> + // operand to a math result.<br>
> + if (match(V, m_Poison()))<br>
> + return PoisonValue::get(V->getType());<br>
> +<br>
> bool IsNan = match(V, m_NaN());<br>
> bool IsInf = match(V, m_Inf());<br>
> bool IsUndef = Q.isUndefValue(V);<br>
><br>
> diff --git a/llvm/test/Transforms/InstSimplify/call.ll b/llvm/test/Transforms/InstSimplify/call.ll<br>
> index 99a4a96d33b1a..721f4941e5110 100644<br>
> --- a/llvm/test/Transforms/InstSimplify/call.ll<br>
> +++ b/llvm/test/Transforms/InstSimplify/call.ll<br>
> @@ -953,7 +953,7 @@ define double @fma_undef_op0(double %x, double %y) {<br>
> <br>
> define double @fma_poison_op0(double %x, double %y) {<br>
> ; CHECK-LABEL: @fma_poison_op0(<br>
> -; CHECK-NEXT: ret double 0x7FF8000000000000<br>
> +; CHECK-NEXT: ret double poison<br>
> ;<br>
> %r = call double @llvm.fma.f64(double poison, double %x, double %y)<br>
> ret double %r<br>
> @@ -969,7 +969,7 @@ define double @fma_undef_op1(double %x, double %y) {<br>
> <br>
> define double @fma_poison_op1(double %x, double %y) {<br>
> ; CHECK-LABEL: @fma_poison_op1(<br>
> -; CHECK-NEXT: ret double 0x7FF8000000000000<br>
> +; CHECK-NEXT: ret double poison<br>
> ;<br>
> %r = call double @llvm.fma.f64(double %x, double poison, double %y)<br>
> ret double %r<br>
> @@ -985,7 +985,7 @@ define double @fma_undef_op2(double %x, double %y) {<br>
> <br>
> define double @fma_poison_op2(double %x, double %y) {<br>
> ; CHECK-LABEL: @fma_poison_op2(<br>
> -; CHECK-NEXT: ret double 0x7FF8000000000000<br>
> +; CHECK-NEXT: ret double poison<br>
> ;<br>
> %r = call double @llvm.fma.f64(double %x, double %y, double poison)<br>
> ret double %r<br>
> @@ -1001,7 +1001,7 @@ define double @fmuladd_undef_op0(double %x, double %y) {<br>
> <br>
> define double @fmuladd_poison_op0(double %x, double %y) {<br>
> ; CHECK-LABEL: @fmuladd_poison_op0(<br>
> -; CHECK-NEXT: ret double 0x7FF8000000000000<br>
> +; CHECK-NEXT: ret double poison<br>
> ;<br>
> %r = call double @llvm.fmuladd.f64(double poison, double %x, double %y)<br>
> ret double %r<br>
> @@ -1017,7 +1017,7 @@ define double @fmuladd_undef_op1(double %x, double %y) {<br>
> <br>
> define double @fmuladd_poison_op1(double %x, double %y) {<br>
> ; CHECK-LABEL: @fmuladd_poison_op1(<br>
> -; CHECK-NEXT: ret double 0x7FF8000000000000<br>
> +; CHECK-NEXT: ret double poison<br>
> ;<br>
> %r = call double @llvm.fmuladd.f64(double %x, double poison, double %y)<br>
> ret double %r<br>
> @@ -1033,7 +1033,7 @@ define double @fmuladd_undef_op2(double %x, double %y) {<br>
> <br>
> define double @fmuladd_poison_op2(double %x, double %y) {<br>
> ; CHECK-LABEL: @fmuladd_poison_op2(<br>
> -; CHECK-NEXT: ret double 0x7FF8000000000000<br>
> +; CHECK-NEXT: ret double poison<br>
> ;<br>
> %r = call double @llvm.fmuladd.f64(double %x, double %y, double poison)<br>
> ret double %r<br>
><br>
> diff --git a/llvm/test/Transforms/InstSimplify/fp-undef-poison.ll b/llvm/test/Transforms/InstSimplify/fp-undef-poison.ll<br>
> index 129d868704c46..6a8036c37b634 100644<br>
> --- a/llvm/test/Transforms/InstSimplify/fp-undef-poison.ll<br>
> +++ b/llvm/test/Transforms/InstSimplify/fp-undef-poison.ll<br>
> @@ -1,8 +1,6 @@<br>
> ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py<br>
> ; RUN: opt < %s -instsimplify -S | FileCheck %s<br>
> <br>
> -; TODO: the instructions with poison operands should return poison<br>
> -<br>
> define float @fadd_undef_op0(float %x) {<br>
> ; CHECK-LABEL: @fadd_undef_op0(<br>
> ; CHECK-NEXT: ret float 0x7FF8000000000000<br>
> @@ -13,7 +11,7 @@ define float @fadd_undef_op0(float %x) {<br>
> <br>
> define float @fadd_poison_op0(float %x) {<br>
> ; CHECK-LABEL: @fadd_poison_op0(<br>
> -; CHECK-NEXT: ret float 0x7FF8000000000000<br>
> +; CHECK-NEXT: ret float poison<br>
> ;<br>
> %r = fadd float poison, %x<br>
> ret float %r<br>
> @@ -29,7 +27,7 @@ define float @fadd_undef_op1(float %x) {<br>
> <br>
> define float @fadd_poison_op1(float %x) {<br>
> ; CHECK-LABEL: @fadd_poison_op1(<br>
> -; CHECK-NEXT: ret float 0x7FF8000000000000<br>
> +; CHECK-NEXT: ret float poison<br>
> ;<br>
> %r = fadd float %x, poison<br>
> ret float %r<br>
> @@ -45,7 +43,7 @@ define float @fsub_undef_op0(float %x) {<br>
> <br>
> define float @fsub_poison_op0(float %x) {<br>
> ; CHECK-LABEL: @fsub_poison_op0(<br>
> -; CHECK-NEXT: ret float 0x7FF8000000000000<br>
> +; CHECK-NEXT: ret float poison<br>
> ;<br>
> %r = fsub float poison, %x<br>
> ret float %r<br>
> @@ -61,7 +59,7 @@ define float @fsub_undef_op1(float %x) {<br>
> <br>
> define float @fsub_poison_op1(float %x) {<br>
> ; CHECK-LABEL: @fsub_poison_op1(<br>
> -; CHECK-NEXT: ret float 0x7FF8000000000000<br>
> +; CHECK-NEXT: ret float poison<br>
> ;<br>
> %r = fsub float %x, poison<br>
> ret float %r<br>
> @@ -77,7 +75,7 @@ define float @fmul_undef_op0(float %x) {<br>
> <br>
> define float @fmul_poison_op0(float %x) {<br>
> ; CHECK-LABEL: @fmul_poison_op0(<br>
> -; CHECK-NEXT: ret float 0x7FF8000000000000<br>
> +; CHECK-NEXT: ret float poison<br>
> ;<br>
> %r = fmul float poison, %x<br>
> ret float %r<br>
> @@ -93,7 +91,7 @@ define float @fmul_undef_op1(float %x) {<br>
> <br>
> define float @fmul_poison_op1(float %x) {<br>
> ; CHECK-LABEL: @fmul_poison_op1(<br>
> -; CHECK-NEXT: ret float 0x7FF8000000000000<br>
> +; CHECK-NEXT: ret float poison<br>
> ;<br>
> %r = fmul float %x, poison<br>
> ret float %r<br>
> @@ -109,7 +107,7 @@ define float @fdiv_undef_op0(float %x) {<br>
> <br>
> define float @fdiv_poison_op0(float %x) {<br>
> ; CHECK-LABEL: @fdiv_poison_op0(<br>
> -; CHECK-NEXT: ret float 0x7FF8000000000000<br>
> +; CHECK-NEXT: ret float poison<br>
> ;<br>
> %r = fdiv float poison, %x<br>
> ret float %r<br>
> @@ -125,7 +123,7 @@ define float @fdiv_undef_op1(float %x) {<br>
> <br>
> define float @fdiv_poison_op1(float %x) {<br>
> ; CHECK-LABEL: @fdiv_poison_op1(<br>
> -; CHECK-NEXT: ret float 0x7FF8000000000000<br>
> +; CHECK-NEXT: ret float poison<br>
> ;<br>
> %r = fdiv float %x, poison<br>
> ret float %r<br>
> @@ -141,7 +139,7 @@ define float @frem_undef_op0(float %x) {<br>
> <br>
> define float @frem_poison_op0(float %x) {<br>
> ; CHECK-LABEL: @frem_poison_op0(<br>
> -; CHECK-NEXT: ret float 0x7FF8000000000000<br>
> +; CHECK-NEXT: ret float poison<br>
> ;<br>
> %r = frem float poison, %x<br>
> ret float %r<br>
> @@ -157,7 +155,7 @@ define float @frem_undef_op1(float %x) {<br>
> <br>
> define float @frem_poison_op1(float %x) {<br>
> ; CHECK-LABEL: @frem_poison_op1(<br>
> -; CHECK-NEXT: ret float 0x7FF8000000000000<br>
> +; CHECK-NEXT: ret float poison<br>
> ;<br>
> %r = frem float %x, poison<br>
> ret float %r<br>
><br>
><br>
> <br>
> _______________________________________________<br>
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</blockquote></div>