fix: don't normalise half turns (#137)

Closes #136 drive-by: cargo update (hugr 0.13.2) I have tested the test in quantinuum-dev/guppy-integration#19 now passes and the example has expected behaviour with crz oracle.
CQCL · Oct 23, 2024 · c73f36b · c73f36b
1 parent 2d9bfce
commit c73f36b
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Showing 4 changed files with 92 additions and 131 deletions.
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/src/extension/rotation.rs b/src/extension/rotation.rs
@@ -14,7 +14,7 @@ use lazy_static::lazy_static;
 
 use crate::{
     custom::CodegenExtsBuilder,
-    emit::{emit_value, get_intrinsic, EmitFuncContext, EmitOpArgs},
+    emit::{emit_value, EmitFuncContext, EmitOpArgs},
     types::TypingSession,
     CodegenExtension,
 };
@@ -138,9 +138,7 @@ impl<PCG: PreludeCodegen> RotationCodegenExtension<PCG> {
         op: RotationOp,
     ) -> Result<()> {
         let ts = context.typing_session();
-        let module = context.get_current_module();
         let builder = context.builder();
-        let angle_ty = llvm_angle_type(&ts);
 
         match op {
             RotationOp::radd => {
@@ -204,27 +202,7 @@ impl<PCG: PreludeCodegen> RotationCodegenExtension<PCG> {
                     .map_err(|_| anyhow!("RotationOp::tohalfturns expects one argument"))?;
                 let half_turns = half_turns.into_float_value();
 
-                // normalised_half_turns is in the interval 0..2
-                let normalised_half_turns = {
-                    // normalised_rads = (half_turns/2 - floor(half_turns/2)) * 2
-                    // note that floor(x) gives the largest integral value less
-                    // than or equal to x so this deals with both positive and
-                    // negative rads.
-                    let turns =
-                        builder.build_float_div(half_turns, angle_ty.const_float(2.0), "")?;
-                    let floor_turns = {
-                        let floor = get_intrinsic(module, "llvm.floor", [angle_ty.into()])?;
-                        builder
-                            .build_call(floor, &[turns.into()], "")?
-                            .try_as_basic_value()
-                            .left()
-                            .ok_or(anyhow!("llvm.floor has no return value"))?
-                            .into_float_value()
-                    };
-                    let normalised_turns = builder.build_float_sub(turns, floor_turns, "")?;
-                    builder.build_float_mul(normalised_turns, angle_ty.const_float(2.0), "")?
-                };
-                args.outputs.finish(builder, [normalised_half_turns.into()])
+                args.outputs.finish(builder, [half_turns.into()])
             }
             op => bail!("Unsupported op: {op:?}"),
         }
@@ -314,7 +292,7 @@ mod test {
 
     #[rstest]
     #[case(ConstRotation::new(1.0).unwrap(), ConstRotation::new(0.5).unwrap(), 1.5)]
-    #[case(ConstRotation::PI, ConstRotation::new(1.5).unwrap(), 0.5)]
+    #[case(ConstRotation::PI, ConstRotation::new(1.5).unwrap(), 2.5)]
     fn exec_aadd(
         mut exec_ctx: TestContext,
         #[case] angle1: ConstRotation,
@@ -350,7 +328,7 @@ mod test {
 
     #[rstest]
     #[case(ConstRotation::PI, 1.0)]
-    #[case(ConstRotation::TAU, 0.0)]
+    #[case(ConstRotation::TAU, 2.0)]
     #[case(ConstRotation::PI_2, 0.5)]
     #[case(ConstRotation::PI_4, 0.25)]
     fn exec_to_halfturns(
@@ -420,13 +398,13 @@ mod test {
 
     #[rstest]
     #[case(1.0, Some(1.0))]
-    #[case(-1.0, Some(1.0))]
+    #[case(-1.0, Some (-1.0))]
     #[case(0.5, Some(0.5))]
-    #[case(-0.5, Some(1.5))]
+    #[case(-0.5, Some (-0.5))]
     #[case(0.25, Some(0.25))]
-    #[case(-0.25, Some(1.75))]
-    #[case(13.5, Some(1.5))]
-    #[case(-13.5, Some(0.5))]
+    #[case(-0.25, Some (-0.25))]
+    #[case(13.5, Some(13.5))]
+    #[case(-13.5, Some (-13.5))]
     #[case(f64::NAN, None)]
     #[case(f64::INFINITY, None)]
     #[case(f64::NEG_INFINITY, None)]

diff --git a/src/extension/snapshots/[email protected] b/src/extension/snapshots/[email protected]
@@ -29,54 +29,45 @@ entry_block:                                      ; preds = %alloca_block
   unreachable
 
 9:                                                ; preds = %entry_block
-  %10 = fdiv double %0, 2.000000e+00
-  %11 = call double @llvm.floor.f64(double %10)
-  %12 = fsub double %10, %11
-  %13 = fmul double %12, 2.000000e+00
-  %14 = fcmp oeq double %13, 0x7FF0000000000000
-  %15 = fcmp oeq double %13, 0xFFF0000000000000
-  %16 = fcmp uno double %13, 0.000000e+00
-  %17 = or i1 %14, %15
-  %18 = or i1 %17, %16
-  %19 = xor i1 %18, true
-  %20 = insertvalue { double } undef, double %13, 0
-  %21 = insertvalue { i32, {}, { double } } { i32 1, {} poison, { double } poison }, { double } %20, 2
-  %22 = select i1 %19, { i32, {}, { double } } %21, { i32, {}, { double } } { i32 0, {} undef, { double } poison }
-  %23 = extractvalue { i32, {}, { double } } %22, 0
-  switch i32 %23, label %24 [
-    i32 1, label %26
+  %10 = fcmp oeq double %0, 0x7FF0000000000000
+  %11 = fcmp oeq double %0, 0xFFF0000000000000
+  %12 = fcmp uno double %0, 0.000000e+00
+  %13 = or i1 %10, %11
+  %14 = or i1 %13, %12
+  %15 = xor i1 %14, true
+  %16 = insertvalue { double } undef, double %0, 0
+  %17 = insertvalue { i32, {}, { double } } { i32 1, {} poison, { double } poison }, { double } %16, 2
+  %18 = select i1 %15, { i32, {}, { double } } %17, { i32, {}, { double } } { i32 0, {} undef, { double } poison }
+  %19 = extractvalue { i32, {}, { double } } %18, 0
+  switch i32 %19, label %20 [
+    i32 1, label %22
   ]
 
-24:                                               ; preds = %9
-  %25 = extractvalue { i32, {}, { double } } %22, 1
+20:                                               ; preds = %9
+  %21 = extractvalue { i32, {}, { double } } %18, 1
   br label %cond_7_case_0
 
-26:                                               ; preds = %9
-  %27 = extractvalue { i32, {}, { double } } %22, 2
-  %28 = extractvalue { double } %27, 0
+22:                                               ; preds = %9
+  %23 = extractvalue { i32, {}, { double } } %18, 2
+  %24 = extractvalue { double } %23, 0
   br label %cond_7_case_1
 
-cond_7_case_0:                                    ; preds = %24
-  %29 = extractvalue { i32, i8* } { i32 1, i8* getelementptr inbounds ([37 x i8], [37 x i8]* @1, i32 0, i32 0) }, 0
-  %30 = extractvalue { i32, i8* } { i32 1, i8* getelementptr inbounds ([37 x i8], [37 x i8]* @1, i32 0, i32 0) }, 1
-  %31 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([34 x i8], [34 x i8]* @prelude.panic_template.1, i32 0, i32 0), i32 %29, i8* %30)
+cond_7_case_0:                                    ; preds = %20
+  %25 = extractvalue { i32, i8* } { i32 1, i8* getelementptr inbounds ([37 x i8], [37 x i8]* @1, i32 0, i32 0) }, 0
+  %26 = extractvalue { i32, i8* } { i32 1, i8* getelementptr inbounds ([37 x i8], [37 x i8]* @1, i32 0, i32 0) }, 1
+  %27 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([34 x i8], [34 x i8]* @prelude.panic_template.1, i32 0, i32 0), i32 %25, i8* %26)
   call void @abort()
   br label %cond_exit_7
 
-cond_7_case_1:                                    ; preds = %26
+cond_7_case_1:                                    ; preds = %22
   br label %cond_exit_7
 
 cond_exit_7:                                      ; preds = %cond_7_case_1, %cond_7_case_0
-  %"0.0" = phi double [ 0.000000e+00, %cond_7_case_0 ], [ %28, %cond_7_case_1 ]
-  %32 = fadd double %0, %"0.0"
+  %"0.0" = phi double [ 0.000000e+00, %cond_7_case_0 ], [ %24, %cond_7_case_1 ]
+  %28 = fadd double %0, %"0.0"
   ret void
 }
 
 declare i32 @printf(i8*, ...)
 
 declare void @abort()
-
-; Function Attrs: nofree nosync nounwind readnone speculatable willreturn
-declare double @llvm.floor.f64(double) #0
-
-attributes #0 = { nofree nosync nounwind readnone speculatable willreturn }