[AArch64][GlobalISel] Legalize s16 G_FCONSTANT to avoid widening to G_CONSTANT #161205
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@llvm/pr-subscribers-llvm-globalisel @llvm/pr-subscribers-backend-aarch64 Author: Ryan Cowan (HolyMolyCowMan) ChangesWhen widening a This PR legalizes Full diff: https://github.com/llvm/llvm-project/pull/161205.diff 1 Files Affected:
diff --git a/llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp b/llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp
index 7ee54c5932b15..1593f32d1fc6c 100644
--- a/llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp
+++ b/llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp
@@ -678,8 +678,8 @@ AArch64LegalizerInfo::AArch64LegalizerInfo(const AArch64Subtarget &ST)
.widenScalarToNextPow2(0)
.clampScalar(0, s8, s64);
getActionDefinitionsBuilder(G_FCONSTANT)
- .legalFor({s32, s64, s128})
- .legalFor(HasFP16, {s16})
+ // Always legalize s16 to prevent G_FCONSTANT being widened to G_CONSTANT
+ .legalFor({s16, s32, s64, s128})
.clampScalar(0, MinFPScalar, s128);
// FIXME: fix moreElementsToNextPow2
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davemgreen
reviewed
Sep 29, 2025
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Yeah this needs to address the regbank regressions. |
aemerson
approved these changes
Oct 6, 2025
|
By moving the |
svkeerthy
pushed a commit
that referenced
this pull request
Oct 9, 2025
…_CONSTANT (#161205) When widening a `G_FCONSTANT` it is converted to a `G_CONSTANT` to avoid loss in accuracy (see #56454). This means that some folds such as `G_FPEXT(G_FCONSTANT)` fail to work when the scalar has been widened. This PR legalizes `s16`s by default in line with how s16 `G_CONSTANT`s are treated.
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When widening a
G_FCONSTANTit is converted to aG_CONSTANTto avoid loss in accuracy (see #56454). This means that some folds such asG_FPEXT(G_FCONSTANT)fail to work when the scalar has been widened.This PR legalizes
s16s by default in line with how s16G_CONSTANTs are treated.